Firewall and SmartDefense

Firewall and SmartDefense
Firewall and SmartDefense
Administration Guide
Version NGX R65
701682 April 27, 2008
© 2003-2007 Check Point Software Technologies Ltd.
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TRADEMARKS:
©2003-2008 Check Point Software Technologies Ltd. All rights reserved. Check Point, AlertAdvisor, Application Intelligence, Check Point Endpoint Security,
Check Point Express, Check Point Express CI, the Check Point logo, ClusterXL, Confidence Indexing, ConnectControl, Connectra, Connectra Accelerator Card,
Cooperative Enforcement, Cooperative Security Alliance, CoreXL, CoSa, DefenseNet, Dynamic Shielding Architecture, Eventia, Eventia Analyzer, Eventia
Reporter, Eventia Suite, FireWall-1, FireWall-1 GX, FireWall-1 SecureServer, FloodGate-1, Hacker ID, Hybrid Detection Engine, IMsecure, INSPECT, INSPECT
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SmartCenter Pro, SmartCenter UTM, SmartConsole, SmartDashboard, SmartDefense, SmartDefense Advisor, Smarter Security, SmartLSM, SmartMap,
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Network Extender, Stateful Clustering, TrueVector, Turbocard, UAM, UserAuthority, User-to-Address Mapping, UTM-1, UTM-1 Edge, UTM-1 Edge Industrial,
UTM-1 Total Security, VPN-1, VPN-1 Accelerator Card, VPN-1 Edge, VPN-1 Express, VPN-1 Express CI, VPN-1 Power, VPN-1 Power Multi-core, VPN-1 Power
VSX, VPN-1 Pro, VPN-1 SecureClient, VPN-1 SecuRemote, VPN-1 SecureServer, VPN-1 UTM, VPN-1 UTM Edge, VPN-1 VSX, Web Intelligence, ZoneAlarm,
ZoneAlarm Anti-Spyware, ZoneAlarm Antivirus, ZoneAlarm ForceField, ZoneAlarm Internet Security Suite, ZoneAlarm Pro, ZoneAlarm Secure Wireless Router,
Zone Labs, and the Zone Labs logo are trademarks or registered trademarks of Check Point Software Technologies Ltd. or its affiliates. ZoneAlarm is a Check
Point Software Technologies, Inc. Company. All other product names mentioned herein are trademarks or registered trademarks of their respective owners. The
products described in this document are protected by U.S. Patent No. 5,606,668, 5,835,726, 5,987,611, 6,496,935, 6,873,988, 6,850,943, and 7,165,076
and may be protected by other U.S. Patents, foreign patents, or pending applications
.For third party notices, see: THIRD PARTY TRADEMARKS AND COPYRIGHTS.
Contents
Preface
Who Should Use This Guide.............................................................................. 16
Summary of Contents ....................................................................................... 17
Section 1: Network Access .......................................................................... 17
Section 2: Connectivity ............................................................................... 18
Section 3: SmartDefense ............................................................................. 19
Section 4: Application Intelligence ............................................................... 19
Section 5: Web Security .............................................................................. 21
Section 6: Appendices ................................................................................ 21
Related Documentation .................................................................................... 22
More Information ............................................................................................. 25
Feedback ........................................................................................................ 26
Network Access
Chapter 1
Access Control
The Need for Access Control ............................................................................. 30
Solution for Secure Access Control .................................................................... 31
Access Control at the Network Boundary ....................................................... 31
The Rule Base ............................................................................................ 32
Example Access Control Rule ....................................................................... 33
Rule Base Elements .................................................................................... 33
Implied Rules............................................................................................. 34
Preventing IP Spoofing ................................................................................ 35
Multicast Access Control ............................................................................. 37
Cooperative Enforcement ............................................................................. 40
End Point Quarantine (EPQ) - Intel(r) AMT .................................................... 42
Special Considerations for Access Control .......................................................... 44
Spoofing Protection..................................................................................... 44
Simplicity .................................................................................................. 44
Basic Rules ................................................................................................ 45
Rule Order ................................................................................................. 45
Topology Considerations: DMZ ..................................................................... 45
X11 Service................................................................................................ 46
Editing Implied Rules.................................................................................. 46
Configuring Access Control ............................................................................... 47
Defining Access Control Rules...................................................................... 47
Defining a Basic Access Control Policy.......................................................... 47
Configuring Anti-Spoofing ............................................................................ 49
Configuring Multicast Access Control ............................................................ 50
Table of Contents
5
Configuring Cooperative Enforcement ...........................................................
Configuring End Point Quarantine (EPQ) - Intel(r) AMT...................................
Activating EPQ ...........................................................................................
Connection Authentication Data ...................................................................
Quarantine Policy Data ................................................................................
Encrypting the Password..............................................................................
Malicious Activity Script and Alert ................................................................
Logging Activity ..........................................................................................
To Quarantine a Machine Manually...............................................................
Chapter 2
51
52
52
53
54
55
55
57
57
Authentication
The Need for Authentication ............................................................................. 60
The VPN-1 Solution for Authentication .............................................................. 61
Introduction to VPN-1 Authentication ........................................................... 61
Authentication Schemes.............................................................................. 62
Authentication Methods............................................................................... 64
Configuring Authentication ............................................................................... 73
Creating Users and Groups........................................................................... 73
Configuring User Authentication................................................................... 75
Configuring Session Authentication .............................................................. 76
Configuring Client Authentication ................................................................. 81
Configuring Authentication Tracking ............................................................. 87
Configuring a VPN-1 Gateway to use RADIUS ................................................ 87
Granting User Access Using RADIUS Server Groups ....................................... 90
Associating a RADIUS Server with a VPN-1 Gateway ...................................... 92
Configuring a VPN-1 Gateway to use SecurID ................................................ 93
Configuring a VPN-1 Gateway to use TACACS+ .............................................. 95
Configuring Policy for Groups of Windows Users............................................. 96
Connectivity
Chapter 3
Network Address Translation (NAT)
The Need to Conceal IP Addresses .................................................................. 100
Check Point Solution for Network Address Translation ....................................... 101
Public and Private IP addresses ................................................................. 101
NAT in VPN-1 .......................................................................................... 102
Static NAT ............................................................................................... 103
Hide NAT................................................................................................. 104
Automatic and Manual NAT Rules .............................................................. 105
Automatic Hide NAT for Internal Networks .................................................. 106
Address Translation Rule Base ................................................................... 107
Bidirectional NAT ..................................................................................... 108
Understanding Automatically Generated Rules............................................. 109
Port Translation ........................................................................................ 111
6
NAT and Anti-Spoofing.............................................................................. 111
Routing Issues.......................................................................................... 111
Disabling NAT in a VPN Tunnel.................................................................. 113
Planning Considerations for NAT ..................................................................... 114
Hide Versus Static .................................................................................... 114
Automatic Versus Manual Rules ................................................................. 114
Choosing the Hide Address in Hide NAT...................................................... 115
Configuring NAT ............................................................................................ 116
General Steps for Configuring NAT ............................................................. 116
Basic Configuration (Network Node with Hide NAT) ..................................... 117
Sample Configuration (Static and Hide NAT) ............................................... 118
Sample Configuration (Using Manual Rules for Port Translation) ................... 120
Configuring Automatic Hide NAT for Internal Networks................................. 121
Advanced NAT Configuration .......................................................................... 122
Allowing Connections Between Translated Objects on Different Gateway Interfaces
122
Enabling Communication for Internal Networks with Overlapping IP Addresses 123
SmartCenter Behind NAT .......................................................................... 127
IP Pool NAT ............................................................................................. 131
Chapter 4
ISP Redundancy
The Need for ISP Link Redundancy ................................................................. 138
Solution for ISP Link Redundancy ................................................................... 139
ISP Redundancy Overview ......................................................................... 139
ISP Redundancy Operational Modes ........................................................... 140
Monitoring the ISP Links ........................................................................... 141
How ISP Redundancy Works ...................................................................... 141
ISP Redundancy Script ............................................................................. 143
Manually Changing the Link Status (fw isp_link) .......................................... 143
ISP Redundancy Deployments.................................................................... 144
ISP Redundancy and VPNs ........................................................................ 147
Considerations for ISP Link Redundancy .......................................................... 149
Choosing the Deployment .......................................................................... 149
Choosing the Redundancy Mode................................................................. 149
Configuring ISP Link Redundancy ................................................................... 150
Introduction to ISP Link Redundancy Configuration ..................................... 150
Registering the Domain and Obtaining IP Addresses..................................... 150
DNS Server Configuration for Incoming Connections .................................... 151
Dialup Link Setup for Incoming Connections ............................................... 152
SmartDashboard Configuration ................................................................... 152
Configuring the Default Route for the ISP Redundancy Gateway .................... 154
Chapter 5
ConnectControl - Server Load Balancing
The Need for Server Load Balancing ................................................................ 158
ConnectControl Solution for Server Load Balancing ........................................... 159
Introduction to ConnectControl................................................................... 159
Load-Balancing Methods ........................................................................... 160
ConnectControl Packet Flow....................................................................... 161
Table of Contents
7
Logical Server Types ................................................................................. 161
Persistent Server Mode.............................................................................. 164
Server Availability ..................................................................................... 166
Load Measuring ........................................................................................ 166
Configuring ConnectControl ............................................................................ 167
Chapter 6
Bridge Mode
Introduction to Bridge Mode ........................................................................... 170
Limitations in Bridge Mode........................................................................ 171
Managing a Gateway in Bridge Mode .......................................................... 171
Configuring Bridge Mode ................................................................................ 172
Bridging Interfaces ................................................................................... 172
Configuring Anti-Spoofing.......................................................................... 172
Displaying the Bridge Configuration ............................................................ 173
SmartDefense
Chapter 7
SmartDefense
The Need for SmartDefense ........................................................................... 178
SmartDefense Solution................................................................................... 180
Introducing SmartDefense ......................................................................... 180
Defending Against the Next Generation of Threats........................................ 181
Network and Transport Layers .................................................................... 182
Web Attack Protection............................................................................... 182
How SmartDefense Works .......................................................................... 183
Online Updates......................................................................................... 184
Categorizing SmartDefense Capabilities ...................................................... 184
SmartDefense Profiles ............................................................................... 186
Monitor-Only Mode ................................................................................... 187
Network Security ........................................................................................... 188
Japanese Language Support for SmartDefense Protections............................ 188
SmartDefense Single Profile View ............................................................... 189
Denial of Service ...................................................................................... 190
IP and ICMP ............................................................................................ 191
TCP ......................................................................................................... 191
Fingerprint Scrambling.............................................................................. 192
Successive Events..................................................................................... 192
DShield Storm Center................................................................................ 192
Port Scan................................................................................................. 193
Dynamic Ports .......................................................................................... 194
Application Intelligence.................................................................................. 195
Mail ........................................................................................................ 195
FTP ......................................................................................................... 195
Microsoft Networks ................................................................................... 195
8
Peer-to-Peer ............................................................................................. 196
Instant Messengers ................................................................................... 196
DNS ........................................................................................................ 196
VoIP ........................................................................................................ 196
SNMP...................................................................................................... 197
Web Intelligence............................................................................................ 198
Web Intelligence Protections...................................................................... 198
Web Intelligence Technologies ................................................................... 199
Web Intelligence and ClusterXL Gateway Clusters ........................................ 199
Web Content Protections ........................................................................... 200
Customizable Error Page............................................................................ 200
Connectivity Versus Security Considerations ................................................ 201
Web Security Performance Considerations ................................................... 203
Backward Compatibility Options for HTTP Protocol Inspection....................... 205
Web Intelligence License Enforcement........................................................ 205
Understanding HTTP Sessions, Connections and URLs................................. 207
Configuring SmartDefense .............................................................................. 210
Updating SmartDefense with the Latest Defenses ........................................ 210
SmartDefense Services................................................................................... 211
Download Updates .................................................................................... 211
Advisories ................................................................................................ 212
Security Best Practices.............................................................................. 213
Configuring SmartDefense Profiles .................................................................. 214
Creating Profiles ....................................................................................... 214
Assign a Profile to the Gateway .................................................................. 214
View Protected Gateways by a Profile .......................................................... 215
SmartDefense StormCenter Module ................................................................. 216
The Need for Cooperation in Intrusion Detection .......................................... 216
Check Point Solution for Storm Center Integration........................................ 217
Planning Considerations ............................................................................ 221
Configuring Storm Center Integration .......................................................... 222
Application Intelligence
Chapter 8
Content Inspection
Anti Virus Protection ...................................................................................... 228
Introduction to Integrated Anti Virus Protection ........................................... 228
Architecture ............................................................................................. 229
Configuring Integrated Anti Virus Scanning.................................................. 229
Database Updates..................................................................................... 230
Understanding Scan By Direction and Scan By IP ........................................ 231
Scanning by Direction: Selecting Data to Scan............................................. 235
File Type Recognition................................................................................ 237
Continuous Download................................................................................ 238
Table of Contents
9
Logging and Monitoring ............................................................................. 239
File Size Limitations and Scanning............................................................. 240
VPN-1 UTM Edge Anti Virus ...................................................................... 242
Web Filtering................................................................................................. 243
Introduction to Web Filtering ..................................................................... 243
Terminology ............................................................................................. 244
Architecture ............................................................................................. 244
Configuring Web Filtering .......................................................................... 245
Chapter 9
Securing Voice Over IP (VoIP)
The Need to Secure Voice Over IP ................................................................... 248
Introduction to the Check Point Solution for Secure VoIP................................... 249
Control Signalling and Media Protocols ............................................................ 250
VoIP Handover............................................................................................... 251
When to Enforce Handover......................................................................... 252
VoIP Application Intelligence .......................................................................... 253
Introduction to VoIP Application Intelligence ............................................... 253
Restricting Handover Locations Using a VoIP Domain................................... 254
Controlling Signalling and Media Connections ............................................. 255
Preventing Denial of Service Attacks........................................................... 255
Protocol-Specific Application Intelligence ................................................... 256
VoIP Logging ................................................................................................. 257
Protocol-Specific Security............................................................................... 258
Securing SIP-Based VoIP................................................................................ 259
SIP Architectural Elements in the Security Rule Base .................................. 260
Supported SIP RFCs and Standards............................................................ 261
Secured SIP Topologies and NAT Support ................................................... 262
Application Intelligence for SIP.................................................................. 264
SmartDefense Application Intelligence for SIP............................................. 265
Synchronizing User Information ................................................................. 267
SIP Services............................................................................................. 267
Using SIP on a Non-Default Port ................................................................ 268
ClusterXL and Multicast Support for SIP ..................................................... 268
Securing SIP-Based Instant Messenger Applications .................................... 268
Configuring SIP-Based VoIP....................................................................... 269
Troubleshooting SIP....................................................................................... 278
Securing H.323-Based VoIP ........................................................................... 279
H.323 Architectural Elements in the Security Rule Base .............................. 279
Supported H.323 RFCs and Standards ....................................................... 280
Secured H.323 Topologies and NAT Support............................................... 280
Application Intelligence for H.323 ............................................................. 283
SmartDefense Application Intelligence Settings for H.323............................ 284
H.323 Services ........................................................................................ 286
Configuring H.323-Based VoIP .................................................................. 287
Securing MGCP-Based VoIP............................................................................ 303
The Need for MGCP .................................................................................. 303
MGCP Protocol and Devices ....................................................................... 304
MGCP Network Security and Application Intelligence ................................... 305
10
Secured MGCP Topologies and NAT Support ............................................... 307
Synchronizing User Information.................................................................. 308
Configuring MGCP-Based VoIP ................................................................... 309
Securing SCCP-Based VoIP............................................................................. 311
The SCCP Protocol.................................................................................... 311
SCCP Devices........................................................................................... 312
SCCP Network Security and Application Intelligence .................................... 312
ClusterXL Support for SCCP ....................................................................... 313
Configuring SCCP-Based VoIP .................................................................... 313
Chapter 10
Securing Instant Messaging Applications
The Need to Secure Instant Messenger Applications.......................................... 320
Introduction to Instant Messenger Security....................................................... 321
Understanding Instant Messenger Security ....................................................... 322
NAT Support for MSN Messenger over SIP ....................................................... 323
NAT Support for MSN Messenger over MSNMS ................................................ 324
Logging Instant Messenger Applications........................................................... 324
Configuring SIP-based Instant Messengers ....................................................... 325
Configuring MSN Messenger over MSNMS ....................................................... 327
Configuring Skype, Yahoo and ICQ and Other Instant Messengers ....................... 328
Chapter 11
Microsoft Networking Services (CIFS) Security
Securing Microsoft Networking Services (CIFS) ................................................. 330
Restricting Access to Servers and Shares (CIFS Resource) ................................. 331
Chapter 12
FTP Security
Introduction to FTP Content Security ............................................................... 334
FTP Enforcement by the VPN-1 Kernel ............................................................ 334
FTP Enforcement by the FTP Security Server.................................................... 335
Control Allowed Protocol Commands ........................................................... 335
Maintaining Integrity of Other Protected Services ......................................... 335
Avoiding Vulnerabilities in FTP Applications ................................................ 335
Content Security via the FTP Resource........................................................ 336
Configuring Restricted Access to Specific Directories ........................................ 337
Chapter 13
Content Security
The Need for Content Security ........................................................................ 340
Check Point Solution for Content Security ........................................................ 341
Introduction to Content Security................................................................. 341
Security Servers........................................................................................ 342
Deploying OPSEC Servers .......................................................................... 343
CVP Servers for Anti-Virus and Malicious Content Protection ......................... 344
Using URL Filtering to Limit Web Surfers.................................................... 348
The TCP Security Server ............................................................................ 351
Configuring Content Security .......................................................................... 352
Resources: What They Are and How to Use Them......................................... 352
Creating a Resource and Using it in the Rule Base ....................................... 353
Table of Contents
11
Configuring Anti-Virus Checking for Incoming Email..................................... 354
Configuring CVP Checking for Web Traffic with Improved Performance........... 356
Configuring URL Filtering with a UFP Server ............................................... 356
Performing CVP or UFP Inspection on any TCP Service................................. 360
Advanced CVP Configuration: CVP Chaining and Load Sharing ........................... 361
Introduction to CVP Chaining and Load Sharing ........................................... 361
CVP Chaining ........................................................................................... 361
CVP Load Sharing ..................................................................................... 363
Combining CVP Chaining and Load Sharing................................................. 364
Configuring CVP Chaining and Load Sharing................................................ 364
Chapter 14
Services with Application Intelligence
Introduction to Services with Application Intelligence........................................ 368
DCE-RPC ...................................................................................................... 368
SSLv3 Service ............................................................................................... 369
SSHv2 Service .............................................................................................. 369
FTP_BASIC Protocol Type............................................................................... 369
Domain_UDP Service ..................................................................................... 370
Point-to-Point Tunneling Protocol (PPTP) ......................................................... 371
Configuring for PPTP................................................................................. 371
Blocking Visitor Mode (TCPT).......................................................................... 373
Introduction to TCPT................................................................................. 373
Why Block Visitor Mode and Outgoing TCPT?............................................... 373
How VPN-1 Identifies TCPT ....................................................................... 373
When to Block Outgoing TCPT ................................................................... 373
Configuration of Visitor Mode Blocking........................................................ 374
Web Security
Chapter 15
Web Content Protection
Introduction to Web Content Protection ........................................................... 378
Web Content Security via the Security Rule Base .............................................. 379
What is a URI Resource? ........................................................................... 379
Filtering URLs, Schemes and Methods by Source and Destination ................. 379
Basic URL Filtering................................................................................... 380
URL Logging ............................................................................................ 380
Java and ActiveX Security .......................................................................... 381
Securing XML Web Services (SOAP) ................................................................ 382
Understanding HTTP Sessions, Connections and URLs...................................... 383
HTTP Request Example............................................................................. 383
HTTP Response Example........................................................................... 384
HTTP Connections .................................................................................... 384
Understanding URLs ................................................................................. 385
Connectivity Versus Security Considerations for Web Surfers .............................. 386
12
Allowing or Restricting Content .................................................................. 386
Content Compression ................................................................................ 387
Factors Affecting HTTP Security Server Performance......................................... 388
The Number of Simultaneous Security Server Connections............................ 388
How To Run Multiple Instances of the HTTP Security Server ......................... 389
Configuring Web Content Protection ................................................................ 390
Blocking URL-based Attacks Using a URI Resource ..................................... 390
Configuring URL Logging ........................................................................... 391
Configuring Basic URL Filtering ................................................................. 392
Appendices
Appendix A
Security Before
VPN-1 Activation
Achieving Security Before VPN-1 Activation ..................................................... 396
Boot Security ................................................................................................ 396
Control of IP Forwarding on Boot ................................................................ 396
The Default Filter...................................................................................... 397
The Initial Policy ........................................................................................... 399
Default Filter and Initial Policy Configuration ................................................... 402
Verifying Default Filter or Initial Policy Loading............................................ 402
Change the Default Filter to a Drop Filter .................................................... 403
User-Defined Default Filter ........................................................................ 403
Using the Default Filter for Maintenance ..................................................... 404
To Unload a Default Filter or an Initial Policy .............................................. 404
If You Cannot Complete Reboot After Installation......................................... 404
Command Line Reference for Default Filter and Initial Policy ........................ 405
Appendix B
Command Line Interface
Index........................................................................................................... 417
Table of Contents
13
14
Preface
P
Preface
In This Chapter
Who Should Use This Guide
page 16
Summary of Contents
page 17
Related Documentation
page 22
More Information
page 25
Feedback
page 26
15
Who Should Use This Guide
Who Should Use This Guide
This guide is intended for administrators responsible for maintaining network
security within an enterprise, including policy management and user support.
This guide assumes a basic understanding of the following:
16
•
System administration
•
The underlying operating system
•
Internet protocols (for example, IP, TCP and UDP)
Summary of Contents
Summary of Contents
This guide describes the firewall and SmartDefense components of VPN-1. It
contains the following sections and chapters:
Section 1: Network Access
This section describes how to secure the networks behind the VPN-1 gateway by
allowing only permitted users and resources to access protected networks.
Chapter
Description
Chapter 1, “Access Control”
Describes how to set up a security policy to fit
organizational requirements.
Chapter 2, “Authentication”
Describes the VPN-1 authentication schemes
(for username and password management) and
authentication methods (how users
authenticate).
Preface
17
Section 2: Connectivity
Section 2: Connectivity
This section describes how to give internal users and resources unrestricted yet
secure connectivity across the gateway.
18
Chapter
Description
Chapter 3, “Network Address
Translation (NAT)”
Describes the Network Address Translation (NAT)
process, which involves replacing one IP address
with another. NAT can change both the source
and destination address of the packet. It is used
for both security and administrative purposes.
Chapter 4, “ISP
Redundancy”
Describes the ISP Redundancy feature, which
assures reliable Internet connectivity by allowing
a single or clustered VPN-1 gateway to connect
to the Internet via redundant Internet Service
Provider (ISP) links.
Chapter 5, “ConnectControl Server Load Balancing”
Describes the ConnectControl server load
balancing solution, which distributes network
traffic among a number of servers and thereby
reduces the load on a single machine, improves
network response time and ensures high
availability.
Section 3: SmartDefense
Section 3: SmartDefense
This section provides an overview of SmartDefense. This VPN-1 component
enables customers to configure, enforce and update network and application
attack defenses. The DShield StormCenter is also described in detail in this
section. For additional information about specific protections, refer to the
SmartDefense HTML pages and the online help.
Chapter
Description
Chapter 7, “SmartDefense”
Describes the SmartDefense component, which
actively defends your network, even when the
protection is not explicitly defined in the
Security Rule Base. SmartDefense unobtrusively
analyzes activity across your network, tracking
potentially threatening events and optionally
sending notifications. It protects your
organization from all known (and most unknown)
network attacks using intelligent security
technology.
Section 4: Application Intelligence
This section describes Check Point Application Intelligence features, which are
a set of advanced capabilities integrated into VPN-1 and SmartDefense to
detect and prevent application-level attacks. The chapters in this section
Preface
19
Section 4: Application Intelligence
describe how to protect against application-level attacks for each application
protocol, and how to work with anti-virus (CVP) and URL filtering (UFP)
applications.
20
Chapter
Description
Chapter 8, “Content
Inspection”
Describes VPN-1 CI (Content Inspection)
gateways, which have integrated Anti Virus
technology. Anti Virus protection is available for
the HTTP, FTP, SMTP and POP3 protocols.
Options for each protocol can be centrally
configured.
Chapter 9, “Securing Voice
Over IP (VoIP)”
Describes how to secure VoIP traffic in H.323,
SIP, MGCP and SCCP environments.
Chapter 10, “Securing
Instant Messaging
Applications”
Describes how to secure SIP-based Instant
Messenger and MSN Messenger applications.
Chapter 11, “Microsoft
Networking Services (CIFS)
Security”
Describes how to secure Microsoft Networking
(CIFS) Services by restricting access to servers
and shares.
Chapter 12, “FTP Security”
Describes how to provide FTP content security
and configure restricted access to specific
directories.
Chapter 13, “Content
Security”
Describes how to integrate with third party
OPSEC-certified antivirus applications and URL
filtering applications.
Chapter 14, “Services with
Application Intelligence”
Describes how to configure protection for some
of the predefined TCP services that perform
content inspection.
Section 5: Web Security
Section 5: Web Security
This section describes the VPN-1 Web Intelligence feature, which provides high
performance attack protection for Web servers and applications, and VPN-1 Web
Content capabilities.
Chapter
Description
Chapter 15, “Web Content
Protection”
Describes the integrated web security
capabilities that are configured through the
Security Rule Base and how to secure XML Web
Services (SOAP) on Web servers.
Section 6: Appendices
This section describes how a VPN-1 gateway protects itself and its networks
during activation and provides a summary of VPN-1 command line interface
commands.
Appendix
Description
Appendix A, “Security Before
VPN-1 Activation”
Describes the Boot Security and Initial Policy
features, which are used when a computer does
not yet have a VPN-1 security policy installed.
Appendix B, “Command Line
Interface”
Describes command line interface commands
that relate to VPN-1 firewall components.
Preface
21
Related Documentation
Related Documentation
This release of VPN-1 includes the following related documentation:
TABLE P-1
22
VPN-1 Power documentation suite documentation
Title
Description
Internet Security Product
Suite Getting Started
Guide
Contains an overview of NGX R65 and step by step
product installation and upgrade procedures. This
document also provides information about What’s
New, Licenses, Minimum hardware and software
requirements, etc.
Upgrade Guide
Explains all available upgrade paths for Check Point
products from VPN-1/FireWall-1 NG forward. This
guide is specifically geared towards upgrading to
NGX R65.
SmartCenter
Administration Guide
Explains SmartCenter Management solutions. This
guide provides solutions for control over
configuring, managing, and monitoring security
deployments at the perimeter, inside the network, at
all user endpoints.
Firewall and
SmartDefense
Administration Guide
Describes how to control and secure network
access; establish network connectivity; use
SmartDefense to protect against network and
application level attacks; use Web Intelligence to
protect web servers and applications; the integrated
web security capabilities; use Content Vectoring
Protocol (CVP) applications for anti-virus protection,
and URL Filtering (UFP) applications for limiting
access to web sites; secure VoIP traffic.
Virtual Private Networks
Administration Guide
This guide describes the basic components of a
VPN and provides the background for the
technology that comprises the VPN infrastructure.
Related Documentation
TABLE P-1
VPN-1 Power documentation suite documentation (continued)
Title
Description
Eventia Reporter
Administration Guide
Explains how to monitor and audit traffic, and
generate detailed or summarized reports in the
format of your choice (list, vertical bar, pie chart
etc.) for all events logged by Check Point VPN-1
Power, SecureClient and SmartDefense.
SecurePlatform™/
SecurePlatform Pro
Administration Guide
Explains how to install and configure
SecurePlatform. This guide will also teach you how
to manage your SecurePlatform machine and
explains Dynamic Routing (Unicast and Multicast)
protocols.
Provider-1/SiteManager-1
Administration Guide
Explains the Provider-1/SiteManager-1 security
management solution. This guide provides details
about a three-tier, multi-policy management
architecture and a host of Network Operating Center
oriented features that automate time-consuming
repetitive tasks common in Network Operating
Center environments.
TABLE P-2
Integrity Server documentation
Title
Description
Integrity Advanced
Server Installation
Guide
Explains how to install, configure, and maintain the
Integrity Advanced Server.
Integrity Advanced
Server Administrator
Console Reference
Provides screen-by-screen descriptions of user
interface elements, with cross-references to relevant
chapters of the Administrator Guide. This document
contains an overview of Administrator Console
navigation, including use of the help system.
Integrity Advanced
Server Administrator
Guide
Explains how to managing administrators and
endpoint security with Integrity Advanced Server.
Integrity Advanced
Server Gateway
Integration Guide
Provides information about how to integrating your
Virtual Private Network gateway device with Integrity
Advanced Server. This guide also contains information
regarding deploying the unified SecureClient/Integrity
client package.
Preface
23
Related Documentation
TABLE P-2
24
Integrity Server documentation (continued)
Title
Description
Integrity Advanced
Server System
Requirements
Provides information about client and server
requirements.
Integrity Agent for Linux
Installation and
Configuration Guide
Explains how to install and configure Integrity Agent
for Linux.
Integrity XML Policy
Reference Guide
Provides the contents of Integrity client XML policy
files.
Integrity Client
Management Guide
Explains how to use of command line parameters to
control Integrity client installer behavior and
post-installation behavior.
More Information
More Information
•
For additional technical information regarding Check Point products, refer to
Check Point’s SecureKnowledge at https://secureknowledge.checkpoint.com/.
•
To view the latest version of this document in the Check Point User Center, go
to: http://www.checkpoint.com/support/technical/documents.
Preface
25
Feedback
Feedback
Check Point is engaged in a continuous effort to improve its documentation. Please
help us by sending your comments to:
cp_techpub_feedback@checkpoint.com
26
Network Access
This section describes how to secure the networks behind the VPN-1 gateway
by allowing only permitted users and resources to access protected networks.
Chapter
Access Control
1
In This Chapter
The Need for Access Control
page 30
Solution for Secure Access Control
page 31
Special Considerations for Access Control
page 44
Configuring Access Control
page 47
29
The Need for Access Control
The Need for Access Control
Network administrators need the means to securely control access to resources
such as networks, hosts, network services and protocols. Determining what
resources can be accessed, and how, is the responsibility of authorization, or
Access Control. Determining who can access these resources is the responsibility of
User Authentication (for additional information, refer to Chapter 2,
“Authentication”).
30
Solution for Secure Access Control
Solution for Secure Access Control
In This Section
Access Control at the Network Boundary
page 31
The Rule Base
page 32
Example Access Control Rule
page 33
Rule Base Elements
page 33
Implied Rules
page 34
Preventing IP Spoofing
page 35
Multicast Access Control
page 37
Cooperative Enforcement
page 40
End Point Quarantine (EPQ) - Intel(r) AMT
page 42
Access Control at the Network Boundary
A VPN-1 gateway at the network boundary inspects and provides access control for
all gateway traffic. Traffic that does not pass though the gateway is not controlled.
Figure 1-1 VPN-1 Gateway Traffic Inspection at the Network Boundary
A security administrator is responsible for implementing company security policy.
VPN-1 allows administrators to enforce security policies consistently across
multiple gateways. To do this, the administrator defines a company-wide security
policy Rule Base using SmartDashboard and installs it to the SmartCenter server.
Chapter 1
Access Control
31
Solution for Secure Access Control
SmartDashboard is a SmartConsole client application that administrators use to
define and apply security policies to gateways. Granular security policy control is
possible by applying specific rules to specific gateways.
VPN-1 provides secure access control because of its granular understanding of all
underlying services and applications traveling on the network. Stateful Inspection
technology provides full application level awareness and comprehensive access
control for more than 150 predefined applications, services and protocols as well
as the ability to specify and define custom services.
Stateful Inspection extracts state-related information required for security decisions
from all application levels and maintains this information in dynamic state tables
that are used to evaluate subsequent connection attempts. For additional technical
information on Stateful Inspection, refer to the Check Point Technical Note at:
http://www.checkpoint.com/products/downloads/firewall-1_statefulinspection.pdf
The Rule Base
A security policy is implemented by means of ordered set of rules in the security
Rule Base. A well defined security policy is essential to an effective security
solution.
The fundamental principle of the Rule Base is that all actions that are not explicitly
permitted are prohibited. The Rule Base is a collection of rules that determine
which communication traffic is permitted and which is blocked. Rule parameters
include the source and destination of the communication, the services and
protocols that can be used and at what times, and tracking options. Reviewing
SmartView Tracker traffic logs and alerts is an crucial aspect of security
management.
VPN-1 inspects packets in a sequential manner. Once VPN-1 receives a packet
from a connection, it inspects it according to the first rule in the Rule Base, and
then the second and so on. Once VPN-1 finds an applicable rule, it stops
inspecting and applies that rule to the packet. If no applicable rule is found in the
Rule Base, the packet is blocked. It is important to understand that the first
matching rule applies to the packet, not necessarily the rule that best applies.
32
Solution for Secure Access Control
Example Access Control Rule
Figure 1-2 displays a typical access control rule. It states that HTTP connections
that originate from any of the Alaska_LAN group hosts, and directed to any
destination will be accepted and logged.
Figure 1-2 Example Access Control Rule
Rule Base Elements
A rule is made up of the following Rule Base elements (not all fields are relevant in
a given rule):
Table 1-1
Rule Base Elements
Source and
Destination
Refers to the originator and recipient of the connection. For applications that
work in the client server model, the source is the client and the destination is
the server. Once a connection is allowed, packets in the connection pass
freely in both directions.
You can negate source and destination parameters, which means that a given
rule applies to all connection sources/destinations except the specified
location. You may, for example, find it more convenient to specify that the a
rule applies to any source that is not in a given network To negate a
connection source or destination, right click on the appropriate rule cell and
select Negate Cell from the options menu.
VPN
Allows you to configure whether the rule applies to any connection (encrypted
or clear) or only to VPN connections. To limit a rule to VPN connections,
double-click on the rule and select one of the two VPN options.
Service
Allows you to apply a rule to specific predefined protocols or services or
applications. You can define new, custom services.
Action
Determines whether a packet is accepted, rejected, or dropped. If a
connection is rejected, VPN-1 sends an RST packet to the originator of the
connection and the connection is closed. If a packet is dropped, no response
is sent and the connection eventually times out. (For information on actions
that relate to authentication, refer to Chapter 2, “Authentication”.
Chapter 1
Access Control
33
Solution for Secure Access Control
Table 1-1
Rule Base Elements
Track
Provides various logging options (for additional information, refer to the
SmartCenter Administration Guide).
Install-On
Specifies the VPN-1 gateways on which the rule is installed. There may be no
need to enforce certain rules on every VPN-1 gateway. For example, a rule
may allow certain network services to cross only one particular gateway. In
this case, the specific rule need not be installed on other gateways. (For
additional information, refer to the SmartCenter Administration Guide.)
Time
Specifies the days and the time of day to enforce this rule.
Implied Rules
Apart from those rules defined by an administrator, VPN-1 also creates implied
rules, which are derived from the Policy > Global Properties definitions. Implied
rules enable certain connections to occur to and from the gateway using a variety of
different services. Examples of implied rules include rules that enable
VPN-1 control connections and outgoing packets originating from the VPN-1
gateway.
VPN-1 implied rules are placed first, last, or before last in the Rule Base and can
be logged. Implied rules are processed in the following order:
1. First: This rule cannot be modified or overwritten in the Rule Base because the
first rule that matches is always applied to the packet and no rules can be
placed before it.
2. Explicit: These are the administrator-defined rules, which may be located
between the first and the before last rules.
3. Before Last: These are more specific rules that are enforced before the last rule
is applied.
4. Rule n: The last defined rule.
5. Last: A rule that is enforced after the last rule in the Rule Base, which normally
rejects all packets and has no effect.
6. Implicit Drop Rule: No logging occurs.
34
Solution for Secure Access Control
Preventing IP Spoofing
IP spoofing occurs when an intruder attempts to gain unauthorized access by
changing a packet's IP address to appear as though it originated from network node
with higher access privileges.
Note - It is important to ensure that all communication originates from its apparent source.
Anti-spoofing protection verifies that packets originate from and are destined to the
correct interfaces on the gateway. It confirms which packets actually come from the
specified internal network interface. It also verifies that once a packet is routed, it
goes through the proper interface.
A packet coming from an external interface, even if it has a spoofed internal IP
address, is blocked because the VPN-1 anti-spoofing feature detects that the
packet arrived from the wrong interface. Figure 1-3 illustrates the anti-spoofing
process.
Figure 1-3 Anti-Spoofing Process
On Alaska_GW, VPN-1 ensures that:
•
All incoming packets to interface IF1 come from the Internet.
•
All incoming packets to interface IF2 come from Alaska_LAN or,
Alaska_RND_LAN or Florida_LAN.
Chapter 1
Access Control
35
Solution for Secure Access Control
On Alaska_RND_GW, VPN-1 ensures that:
•
All incoming packets to interface IF3 come from Alaska_LAN, Florida_LAN or
the Internet.
•
All incoming packets to interface IF4 come from Alaka_RND_LAN.
When configuring anti-spoofing, you need to specify in the interface topology
definitions whether the interfaces lead to the Internet (defined as External) or an
internal network (defined as Internal). Figure 1-3 illustrates whether the gateway
interfaces are internal or external in the interface topology definitions.
Excluding Specific Internal Addresses from
Anti-Spoofing Protection
In some cases, it may be necessary to allow packets with source addresses that
belong to an internal network to enter the gateway through an external interface.
This may be useful if an external application assigns internal IP addresses to
external clients. In this case, you can specify that anti-spoofing checks are not
made on packets from specified internal networks. For example, in Figure 1-3, it is
possible to specify that packets with source addresses in Alaska_RND_LAN are
allowed to enter interface IF1.
What Are Legal Addresses?
Legal addresses are those addresses that are permitted to enter a VPN-1 gateway
interface. Legal addresses are determined by the network topology. When
configuring VPN-1 anti-spoofing protection, the administrator specifies the legal IP
addresses behind the interface. The Get Interfaces with Topology option
automatically defines the interface and its topology and creates network objects.
VPN-1 obtains this information by reading routing table entries.
Additional Information
For additional information on anti-spoofing protection planning, refer to “Spoofing
Protection” on page 44.
For additional information on anti-spoofing configuration, refer to “Configuring
Anti-Spoofing” on page 49.
36
Solution for Secure Access Control
Multicast Access Control
In This Section
Introduction to Multicast IP
page 37
Multicast Routing Protocols
page 37
Dynamic Registration Using IGMP
page 38
IP Multicast Group Addressing
page 38
Per-Interface Multicast Restrictions
page 39
Introduction to Multicast IP
Multicast IP transmits a single message to a predefined group of recipients. an
example of this is distributing real-time audio and video to a set of hosts that have
joined a distributed conference.
Multicast is similar to radio and TV where only those people who have tuned their
tuners to a selected frequency receive the information. With multicast you hear the
channel you are interested in, but not the others.
IP multicasting applications send one copy of each datagram (IP packet) and
address it to a group of computers that want to receive it. This technique sends
datagrams to a group of recipients (at the multicast address) rather than to a single
recipient (at a unicast address). The routers in the network forward the datagrams
to only those routers and hosts that want to receive them.
The Internet Engineering Task Force (IETF) has developed multicast communication
standards that define:
•
Multicast routing protocols
•
Dynamic registration
•
IP multicast group addressing
Multicast Routing Protocols
Multicast routing protocols communicate information between multicast groups.
Examples of multicast routing protocols include Protocol-Independent Multicast
(PIM), Distance Vector Multicast Routing Protocol (DVMRP), and Multicast
Extensions to OSPF (MOSPF).
Chapter 1
Access Control
37
Solution for Secure Access Control
Dynamic Registration Using IGMP
Hosts use the Internet Group Management Protocol (IGMP) to let the nearest
multicast router know if they want to belong to a particular multicast group. Hosts
can leave or join the group at any time. IGMP is defined in RFC 1112.
IP Multicast Group Addressing
The IP address area has four sections: Class A, Class B, Class C, and Class D. Class
A, B, and C addresses are used for unicast traffic. Class D addresses are reserved
for multicast traffic and are allocated dynamically.
The multicast address range 224.0.0.0 through 239.255.255.255 is used only for
the group address or destination address of IP multicast traffic. Every IP datagram
whose destination address starts with 1110 is an IP multicast datagram
(Figure 1-4).
Figure 1-4 Multicast Address Range
Just as a radio is tuned to receive a program that is transmitted at a certain
frequency, a host interface can be tuned to receive datagrams sent to a specific
multicast group. This process is called joining a multicast group.
The remaining 28 bits of the multi-case address range identify the multicast group
to which the datagram is sent. Membership in a multicast group is dynamic (hosts
can join and leave multicast groups). The source address for multicast datagrams is
always the unicast source address.
Reserved Local Addresses
Multicast group addresses in the 224.0.0.0 through 224.0.0.255 range are
assigned by the Internet Assigned Numbers Authority (IANA) for applications that
are never forwarded by a router (they remain local on a particular LAN segment).
38
Solution for Secure Access Control
These addresses are called permanent host groups. Table 1-2 provides examples of
reserved Local Network Multicast Groups.
Table 1-2
Local Network Multicast Groups Examples
Multicast Address
Purpose
224.0.0.1
All hosts. An ICMP Request (ping) sent to this group
should be answered by all multicast capable hosts on the
network. Every multicast capable host must join this group
at start up on all of its multicast capable interfaces.
224.0.0.2
All routers. All multicast routers must join this group on all
of its multicast capable interfaces.
224.0.0.4
All DVMRP routers.
224.0.0.5
All OSPF routers.
224.0.0.13
All PIM routers.
For additional information on reserved multicast addresses, refer to:
http://www.iana.org/assignments/multicast-addresses.
Per-Interface Multicast Restrictions
A multicast enabled router forwards multicast datagrams from one interface to
another. When you enable multicast on a VPN-1 gateway running on
SecurePlatform, you can define multicast access restrictions on each interface
(refer to Figure 1-5). These restrictions specify which multicast groups (addresses
or address ranges) to allow or to block. Enforcement is performed on outbound
multicast datagrams.
When access is denied to a multicast group on an interface for outbound IGMP
packets, inbound packets are also denied.
Chapter 1
Access Control
39
Solution for Secure Access Control
Figure 1-5
Gateway with Per Interface Multicast Restrictions
When access restrictions for multicast datagrams are not defined, inbound
multicast datagrams entering a gateway from one interface are allowed out of all
other interfaces.
In addition to defining per interface access restrictions, you must define a rule in
the Rule Base that allows multicast traffic and services, and the destination
defined in this rule must allow the required multicast groups.
For additional information, refer to “Configuring Multicast Access Control” on
page 50.
VPN Connections
Multicast traffic can be encrypted and sent across VPN links defined using multiple
VPN tunnel interfaces (virtual interfaces associated with the same physical
interface).
Cooperative Enforcement
Cooperative Enforcement works with Check Point Integrity servers. This feature
utilizes the Integrity server compliance capability to verify connections arriving from
various hosts across the internal network.
40
Solution for Secure Access Control
Integrity server is a centrally managed, multi-layered endpoint security solution that
employs policy-based security enforcement for internal and remote PCs. Easily
deployed and managed, the Integrity server mitigates the risk of hackers, worms,
spyware, and other security threats.
Features such as predefined policy templates, an intuitive web-based management
interface, and PC firewall and application privilege controls, enable administrators
to develop, manage, and enforce Cooperative Enforcement quickly and easily.
Using Cooperative Enforcement, any host initiating a connection through a gateway
is tested for compliance. This increases the integrity of the network because it
prevents hosts with malicious software components from accessing the network.
This feature acts as a middle-man between hosts managed by an Integrity server
and the Integrity server itself. It relies on the Integrity server compliance feature,
which defines whether a host is secure and can block connections that do not meet
the defined prerequisites of software components.
The following is a typical Cooperative Enforcement workflow:
1. A host opens a connection to the network through a firewall gateway. The first
packet from the client to the server is allowed. It is only on the first server's
reply to the client that the Cooperative Enforcement feature begins to perform.
2. The firewall checks for host compliance in its tables and queries the Integrity
server, if required.
3. Upon receiving a reply, connections from compliant hosts are allowed and
connections from non-compliant hosts are blocked.
When activating the cooperative enforcement feature on a gateway, the following
implied rules are automatically enabled:
1. Allow all firewall GUI clients to connect to the integrity server via HTTP or
HTTPS (port 80 or 443).
2. Allow all internal clients to access the Integrity server via the firewall for
heartbeats.
3. Allow the firewall to communicate with the Integrity server on port 5054.
If additional access permissions are required (such as allow external clients to
connect to the integrity server, or for other machines to access the administration
portion of the Integrity server), explicit rules should be defined.
If additional access permissions are required (such as allow external clients to
connect to the integrity server, or for other machines to access the administration
portion of the Integrity server), explicit rules should be defined.
Chapter 1
Access Control
41
Solution for Secure Access Control
Enforcement Mode
When in enforcement mode, noncompliant host connections are blocked by the
firewall endpoint security feature. For HTTP connections, the host is notified that it
is noncompliant. The user can then perform appropriate actions to achieve
compliance. For example, the user may upgrade the version of the Integrity client.
NAT Environments
Cooperative Enforcement feature is not supported by all the NAT configurations.
In order for Cooperative Enforcement to work in a NAT environment, the
enforcement module and the Integrity Server must relate to the same IP address of
a specific client. Therefore, when NAT is used, if NAT is causing the Client IP
received by gateway to be different than the Client IP received by the Integrity
Server, Cooperative Enforcement will not work properly.
Monitor Only Deployment Mode
In the “monitor only” deployment mode, the firewall requests authorization
statuses from the Integrity server but, regardless of the received statuses,
connections are not dropped. In addition (if configured by the administrator) the
Cooperative Enforcement feature generates logs regardless of the deployment
mode.
For configuration details, see “Configuring Cooperative Enforcement” on page 51.
End Point Quarantine (EPQ) - Intel(r) AMT
End Point Quarantine (using Intel® AMT) gives the administrator the ability to place
a malicious user’s machine under quarantine whenever malicious activity takes
place according to the security policy configuration.
EPQ isolates the malicious machine by installing a security policy on the machine
where the malicious activity originated. The policy restricts both inbound and
outbound traffic flowing from that machine. As a result, the machine is isolated
from the rest of the network and is prevented from causing any further problems.
It is recommended to enable anti-spoofing to maximize the security protection.
Even with anti-spoofing enabled, the following protections will not work properly
with EPQ and may cause hosts to be put into quarantine:
42
•
All DOS protections
•
Packet sanity
Solution for Secure Access Control
•
Max ping size
•
IP fragment
•
Network quota
•
Small pmtu
EPQ is supported on SecurePlatform and Linux platforms.
For configuration details, see “Configuring End Point Quarantine (EPQ) - Intel(r)
AMT” on page 52.
Chapter 1
Access Control
43
Special Considerations for Access Control
Special Considerations for Access Control
In This Section
Spoofing Protection
page 44
Simplicity
page 44
Basic Rules
page 45
Rule Order
page 45
Topology Considerations: DMZ
page 45
Editing Implied Rules
page 46
Defining Access Control Rules
page 47
Spoofing Protection
If your network is not protected against IP address spoofing, your access control
rules are ineffective and it is easy for attackers to gain access by changing the
source address of the packet. For this reason, ensure that you configure
anti-spoofing protection on every interface of the VPN-1 gateway, including internal
interfaces. For configuration information, refer to “Configuring Access Control” on
page 47.
Simplicity
The key to effective firewall protection is a simple Rule Base. One of the greatest
dangers to the security of your organization is misconfiguration. For example, a user
may try to sneak spoofed, fragmented packets past your firewall if you have
accidentally allowed unrestricted messaging protocols. To keep your Rule Base
simple, ensure that it is concise and therefore easy to understand and maintain.
The more rules you have, the more likely you are to make a mistake.
44
Special Considerations for Access Control
Basic Rules
When creating rules, ensure that you allow only traffic that you want. Consider
traffic initiated and crossing the firewall from both the protected and unprotected
sides of the firewall.
The following basic access control rules are recommended for every Rule Base:
•
A Stealth Rule to prevent direct access to the VPN-1 gateway.
•
A Cleanup Rule to drop all traffic that is not permitted by the previous rules.
There is an implied rule that does this, but the Cleanup Rule allows you to log
such access attempts.
Remember that the fundamental concept behind the Rule Base is that actions that
are not explicitly permitted are prohibited.
Rule Order
Rule order is a critical aspect of an effective Rule Base. Having the same rules, but
putting them in a different order, can radically alter the effectiveness of your
firewall. It is best to place more specific rules first and more general rules last.
This order prevents a general rule from being applied before a more specific rule
and protects your firewall from misconfigurations.
Topology Considerations: DMZ
If you have servers that are externally accessible from the Internet, it is
recommended to create a demilitarized zone (DMZ). The DMZ isolates all servers
that are accessible from untrusted sources, such as the Internet, so that if one of
those servers is compromised, the intruder only has limited access to other
externally accessible servers. Servers in the DMZ are accessible from any network,
and all externally accessible servers should be located in the DMZ. Servers in the
DMZ should be as secure as possible. Do not allow the DMZ to initiate connections
into the internal network, other than for specific applications such as
UserAuthority.
Chapter 1
Access Control
45
Special Considerations for Access Control
X11 Service
The X11 (X Window System Version 11) graphics display system is the standard
graphics system for the Unix environment. To enable X11, you must create a
specific rule using the X11 service. If you select Any as the Source or Destination,
the X11 service is not included because when using the X11 service, the GUI
application acts as the server rather than the client.
Editing Implied Rules
Implied rules are defined in the Global Properties window, which is accessed from
the Firewall Implied Rules page. In general, there is no need to change predefined
implied rules. It is often best to leave some of the rules unselected so that the
property can be controlled with greater granularity through the Rule Base. For
example, you may want to allow ICMP pings across certain gateways only.
The following are the recommended settings for implied rules:
Table 1-3
46
Recommended Settings for Firewall Implied Rules
Implied Rule
Recommended Setting
Accept VPN-1 control connections
First
Accept Remote Access control connections
First
Accept SmartUpdate connections
First
Accept outbound packets originating from the
gateway
Unselected
Accept RIP
Unselected
Accept Domain Name Over UDP (Queries)
Unselected
Accept Domain Name over TCP (Zone transfer)
Unselected
Accept ICMP requests
Unselected
Accept dynamic address modules’ DHCP traffic
First
Accept VRRP packets originating from cluster
members (VSX Nokia VRRP)
First
Configuring Access Control
Configuring Access Control
In This Section
Defining Access Control Rules
page 47
Defining a Basic Access Control Policy
page 47
Configuring Anti-Spoofing
page 49
Configuring Multicast Access Control
page 50
Configuring Cooperative Enforcement
page 51
Configuring End Point Quarantine (EPQ) - Intel(r) AMT
page 52
Defining Access Control Rules
To view an example of an access control rule, refer to Figure 1-3 on page 35.
To define access control rules. perform the following steps using SmartDashboard
(for additional information, refer to the SmartCenter Administration Guide):
1. Define network objects for each network and host using SmartDashboard.
2. Click the Security tab in the Rule Base.
3. From the SmartDashboard menu, select Rules > Add Rule and then select either
Bottom, Top, Below, or Above.
4. Right-click in the Source and Destination columns and select Add....
5. Select a network object and click OK.
6. Right-click in the Service column and select Add....
7. Select a service or a service group and click OK.
8. Right-click in the Action column and select Accept, Drop, or Reject.
9. Right-click in the Track column and select Add....
10. Select one of the tracking options.
Defining a Basic Access Control Policy
The Access Control policy is required to:
•
Allow internal users access to the Internet.
•
Allow all users access to the servers on the DMZ network.
Chapter 1
Access Control
47
Configuring Access Control
•
Protect the network from outsiders.
The policy also requires two basic rules: a Stealth rule and a Cleanup rule.
Figure 1-6 illustrates a sample network that requires an Access Control policy.
Figure 1-6 Sample Network Requiring an Access Control Policy
To create an Access Control Policy:
• Add rules in SmartDashboard using the Rules > Add Rules... menu options.
Figure 1-7 Sample Access Control Rule Base
For additional information, refer to “Defining a Basic Access Control Policy” on
page 47.
48
Configuring Access Control
Configuring Anti-Spoofing
It is important to configure anti-spoofing protection on every interface of every
VPN-1 gateway, including internal interfaces. The following configuration example
describes how to define anti-spoofing parameters on external and internal
interfaces.
Defining Addresses for External Interfaces
To define a valid address for external interfaces:
1. In SmartDashboard, select Manage > Network Objects.
2. Select a gateway and click the Edit button.
3. From the Network Properties list, select Topology.
4. Select Get > Interfaces to obtain interface information of the gateway machine.
5. Select the interface that faces the Internet and click Edit.
6. In the Interface Properties window, click Topology, and then select External
(leads out to the Internet).
7. Select Perform Anti-Spoofing based on interface topology.
8. To ensure that anti-spoofing verification does not occur for addresses coming
from certain internal networks into the external interface, define a network
object that represents those internal networks. Select Don't check packets from:
and then select the network object from the drop-down list.
9. Under Spoof Tracking, select Log and then click OK.
Defining Addresses for Internal Interfaces
To define a valid address for internal interfaces:
1. In SmartDashboard, select Manage > Network Objects.
2. Select the Check Point gateway and right-click Edit.
3. From the Properties list, select Topology.
4. Select Get > Interfaces to obtain interface information of the gateway machine.
5. Under the Name column, select the internal interface and click Edit.
6. In the Interface Properties window, click Topology, and then select Internal (leads
to the local network).
7. Under IP Addresses behind this interface, do one of the following:
Chapter 1
Access Control
49
Configuring Access Control
•
If there is only one network behind the interface, select Network defined by
the interface IP and Net Mask.
•
If there is more than one network behind the interface, define a group
network object that consists of all the networks behind the interface by
selecting Specific and the group.
8. To verify Perform Anti-Spoofing based on interface topology, under Spoof Tracking,
select Log and click OK.
9. Repeat step 1 to step 8 for all internal interfaces.
10. Install the security policy.
Configuring Multicast Access Control
For additional information on multicast access control, refer to: “Multicast Access
Control” on page 37.
To configure multicast access control:
1. In the gateway General Properties page, ensure that the gateway version is
specified correctly. (A per-interface multicast policy can be defined for
gateways of versions R60 or higher.)
2. In the Topology page, edit an interface.
3. In the Multicast Restrictions tab of the Interface Properties window, (Figure 1-8),
select the Drop Multicast packets by the following conditions option.
50
Configuring Access Control
Figure 1-8
Multicast Restrictions Tab in the Interface Properties Window,
4. Define either a restrictive or a permissive multicast policy for the interface by
selecting one of the following options:
•
Drop multicast packets whose destination is in the list
•
Drop all multicast packets except those whose destination is in the list
5. Click New to add a multicast address range. The Multicast Address Range
Properties window opens.
6. Define either an IP address Range or a Single IP Address that are in the
224.0.0.0 to 239.255.255.255 range.
7. In the Rule Base, add a rule that allows the required multicast groups.
8. As the Destination of the rule, specify the multicast groups defined in step 5.
9. Save and install the security policy.
Configuring Cooperative Enforcement
To configure Cooperative Enforcement:
From the gateway’s Cooperative Enforcement page, select Authorize clients using
Integrity Server to enable Cooperative Enforcement.
Chapter 1
Access Control
51
Configuring Access Control
1. Select Monitor Only for traffic to pass successfully and to track only connections
that would otherwise have been dropped.
2. Track unauthorized client status allows you to set the appropriate track or alert
option. The default setting is Log.
3. In the Integrity Server Selection section, select which Integrity server will be
used:
•
To use this machine, select Use Integrity Server installed on this machine.
•
To use another machine, select a server from the Select Integrity Server drop
down menu. Click New to create a new server.
4. In the Client Authorization section, select one of the following methods:
•
Check authorization of all clients: Inspects all clients.
•
Bypass authorization of the following clients: Permits all clients in the
selected groups drop-down list to pass without inspection.
•
Check authorization only of the following clients: Verifies the authorization of
clients from the selected groups drop-down list.
Configuring End Point Quarantine (EPQ) - Intel(r)
AMT
Configuring EPQ is done using CLI. The following tables illustrate how to configure
the AMT.conf file. The AMT.conf file, which is located in the $FWDIR/conf
folder, is used to define all actions taken on the machine initiating any malicious
action.
Activating EPQ
By default, EPQ is disabled. To enable, proceed in the AMT.conf file:
1. On the enable_amt line, change false to true.
2. See Table 1-4, Table 1-5, and Table 1-6 for further configuration samples.
3. Install policy.
52
Configuring Access Control
Table 1-4
Configuration sample
----- Activate the feature by changing the flag to true and define
the subnets the feature is enabled on.
:enable_amt (false)
----- AMT Quarantine can be activated on a host, on a network, or
both
:apply_on (
:(host
:ipaddr (192.168.10.1)
)
:(network
:ipaddr_from (192.168.10.1)
:ipaddr_to (192.168.10.100)
)
)
:track (log)
Connection Authentication Data
Table 1-5
Defining the Authentication Method
:authentication (
----- Define the authentication method using on of the following:
no_tls - clear text
tls - only server authentication
mutual_tls - client and server authentication
:method (no_tls)
----- Username and password are required for all methods
:user_name (“admin”)
:user_pass (“Myadmin1!”)
----- Server Certificate is only required when tls is the chosen
authentication method
:server_certificate (
:server_cert_name (“server certificate name”)
:server_cert_path (“server certificate path”)
)
----- Client certificate is only relevant on Linux when mutual_tls
is the chosen authentication method
:client_certificate (
:cert_name ("certificate name")
:cert_pass ("certificate pass")
)
)
Chapter 1
Access Control
53
Configuring Access Control
Quarantine Policy Data
Table 1-6
Policy Name and Rules
:quarantine_policy_data (
:policy_name ("CP_Qua")
----- Format for the policy version is MMDDHHmm (month, day, hour,
minutes)
:policy_ver ("23121917")
----- Define the rules for traffic directed to the machine initiating
the malicious activity
:incoming (
:1 (
:name ("dns")
:service (
:protocol (udp) # tcp / udp
:port (53)
)
:address ("10.16.70.5")
:address_mask ("255.255.255.0")
)
:2 (
:name ("ftp")
:service (
:protocol (udp)
:port (21)
)
:address ("10.16.70.5")
:address_mask ("255.255.255.0")
)
-----Define the rules for traffic flowing from the machine initiating
the malicious acitivity
:outgoing (
:1 (
:name ("dns")
:service (
:protocol (udp) # tcp / udp
:port (53)
)
:address ("10.16.70.5")
:address_mask ("255.255.255.0")
)
:2 (
:name ("ftp")
:service (
:protocol (udp)
:port (21)
)
:address ("10.16.70.5")
:address_mask ("255.255.255.0")
)
54
Configuring Access Control
You can configure up to 29 rules for incoming traffic and up to 29 rules outgoing
traffic.
The policy name must begin with “CP_” and cannot exceed six letters. Numbers
and other characters are not permitted.
Note - It is recommended not to change the default policy name.
Encrypting the Password
After the AMT.conf file is configured and saved, run the following command:
epq -o set_password
This command will not change the password but will encrypt the password so it is
not in the clear. Running this command a second time however, will change the
password. It is recommended to save and store your password in a safe place since
there is no undo option.
Malicious Activity Script and Alert
The sam_alert tool executes FW-1 SAM actions according to information received
through Standard input (the log mechanism). This tool is to be used for executing
FW-1 SAMv2 actions with the user defined alerts mechanism.
Usage
sam_alert [-O] [-S] [-t timeout] [-f target] [-n name] -[c comment] [-o originator] [-l
r|a] -a d|r|n|b|q|i [-C] -ip -eth -src -dst -srv -any
Table 1-7 describes the arguments for this command.
Table 1-7
Argument
Description
-O
print the input of this tool to Standard output (for pipes).
-S
Match the SAM server to be contacted. Default is localhost.
-t timeout
The time period (in seconds) for which the action will be
enforced. The default is forever.
-f target
The firewalls on which to run the operation. Default is All.
Chapter 1
Access Control
55
Configuring Access Control
Table 1-7
Argument
Description
-n name
Fill in the SAM name field. Default is empty.
-c comment
Fill in the SAM comment field. Default is empty.
-o originator
Fill in the SAM originator field. Default is "sam_alert".
-l
Logs to issue for connections matching the specified criteria.
Either r/egular, a/lert. Default is None.
-a
Action to apply on connections matching specified criteria.
Either d/rop, r/eject, n/otify, b/ypass, q/uarantine, i/nspect.
-C
Close all existing connections that match the criteria.
-ip
Use IP addresses as criteria parameters.
-eth
Use MAC addresses as criteria parameters.
-src
Match the source address of connections.
-dst
Match the destination address of connections.
-srv
Match specific source, destination, protocol and service.
-any
Match either the source or destination address of connections.
Configuration
In SmartDashboard:
1. Click Policy > Global Properties > Log and Alert > Alert Commands.
2. In one of the unused Run UserDefined script fields, enter the following script
command:
sam_alert -v2 -a r -t 60 -ip -src
This is a sample script. Keep in mind the following points:
•
The feature will only work if the action (-a) is r (reject) or d (drop).
•
-t 60 can be changed.
•
-ip and -src represent that we only want to block an attacker that sends
something malicious.
3. Install policy.
56
Configuring Access Control
Logging Activity
The script is run when a malicious action is logged.
Note - Actions are not logged by default. The User Defined alert must be enabled for each
threat for the sam_alert script to be activated.
The log as it appears in SmartView Tracker.
The first log entry represents that the end point host, Broadwater, has been
quarantined The second log represents that the end point host, broadwater, has
been released from quarantine and authorized to be part of the network.
To Quarantine a Machine Manually
A machine can be quarantined manually using the following command:
epq -o < status | list | is_amt | enable | disable [-l
lastPolicyHandle] > -i AMTdeviceIP [policyFileName]
Table 1-8 describes the arguments for this command.
Table 1-8
Argument
Description
status
Display the status of the policies and rules.
list
List the quarantined end-point computers.
is_amt
Allows the user to check if there is AMT on the
machine.
enable
Activates the policy.
disable
Deactivates the policy being enforced.
-l lastPolicyHandle
This is the last known policy to be activated.
-i AMTdeviceIP
The IP address of the end-point computer you
want to quarantine.
policyFileName
The file name of the file containing the policy you
want to enforce. (default location is $FWDIR/conf/AMT.conf)
Chapter 1
Access Control
57
Configuring Access Control
58
Chapter
Authentication
2
In This Chapter
The Need for Authentication
page 33
The VPN-1 Solution for Authentication
page 34
Configuring Authentication
page 46
32
The Need for Authentication
The Need for Authentication
Authentication confirms the identity of valid users authorized to access your
company network. Staff from different departments are assigned access
permissions based on their level of responsibility and role within the organization.
Authentication ensures that all users trying to access the system are valid users,
but does not define their access rights.
33
The VPN-1 Solution for Authentication
The VPN-1 Solution for Authentication
In This Section
Introduction to VPN-1 Authentication
page 34
Authentication Schemes
page 35
Authentication Methods
page 37
Introduction to VPN-1 Authentication
VPN-1 authenticates individual users using credentials and manages them using
different authentication schemes. All of the authentication schemes require the
provision of a username and password. While some schemes involve storing the
passwords on the VPN-1 gateway, others are stored on external servers.
There are three ways to access a network resource and authenticate using VPN-1:
User Authentication: Enables administrators to permit users who have temporarily
left their desk to work on the local network without extending access to all users on
the same host. User authentication is available only for the Telnet, FTP, HTTP and
RLOGIN services.
Session Authentication: Provides an authentication mechanism for any service and
requires users to supply their credentials for each authentication session. A session
authentication agent must be installed on every authenticating client, therefore this
method is not suitable for authenticating HTTP services as they open multiple
connections per session. Similar to client authentication, it is best used on single
user machines, where only one user can authenticate from a given IP at any one
time.
Client Authentication: Permits multiple users and connections from the authorized
IP address or host. Authorization is performed per machine. For example, if
FINGER is authorized for a client machine, then all users on the client are
authorized to use FINGER and are not asked to supply a password during the
authorization process. Client authentication is best enabled on single-user
machines.
The main advantage of client authentication is that it can be used on any number
of connections for any service and authentication can be set to valid for a specified
time period.
These authentication methods can also be used for unencrypted communication.
Chapter 2
Authentication
34
The VPN-1 Solution for Authentication
Authentication is required for Remote Access communication using
SecuRemote/SecureClient.
Authentication Schemes
Authentication schemes employ usernames and passwords to identify valid users.
Some schemes are maintained locally and store usernames and passwords on the
VPN-1 gateway, while others are maintained externally and store user
authentication information on an external authentication server. Certain schemes,
such as SecurID, are based on providing a one-time password. All of the schemes
can be used with users defined on an LDAP server. For additional information on
configuring VPN-1 to integrate with an LDAP server, refer to the SmartDirectory
(LDAP) and User Management section in the SmartCenter Administration Guide.
Check Point Password
VPN-1 can store a static password in the local user database of each user
configured in SmartCenter server. No additional software is required.
Operating System Password
VPN-1 can authenticate using the username and password that is stored on the
operating system of the machine on which VPN-1 is installed. You can also use
passwords that are stored in a Windows domain. No additional software is required.
RADIUS
Remote Authentication Dial-In User Service (RADIUS) is an external authentication
scheme that provides security and scalability by separating the authentication
function from the access server.
Using RADIUS, VPN-1 forwards authentication requests by remote users to the
RADIUS server. The RADIUS server, which stores user account information,
authenticates the users.
The RADIUS protocol uses UDP to communicate with the gateway. RADIUS servers
and RADIUS server group objects are defined in SmartDashboard. For additional
information on configuring RADIUS, refer to “Configuring a VPN-1 Gateway to use
RADIUS” on page 60.
35
The VPN-1 Solution for Authentication
SecurID
SecurID requires users to both possess a token authenticator and to supply a PIN
or password. Token authenticators generate one-time passwords that are
synchronized to an RSA ACE/server and may come in the form of hardware or
software. Hardware tokens are key-ring or credit card-sized devices, while software
tokens reside on the PC or device from which the user wants to authenticate. All
tokens generate a random, one-time use access code that changes approximately
every minute. When a user attempts to authenticate to a protected resource, the
one-time use code must be validated by the ACE/server.
Using SecurID, VPN-1 forwards authentication requests by remote users to the
ACE/server. ACE manages the database of RSA users and their assigned hard or
soft tokens. The VPN-1 gateway acts as an ACE/Agent 5.0 and directs all access
requests to the RSA ACE/server for authentication. For additional information on
agent configuration, refer to ACE/server documentation.
There are no specific parameters required for the SecurID authentication scheme.
For additional information on configuring SecurID, refer to “Configuring a VPN-1
Gateway to use SecurID” on page 66.
TACACS
Terminal Access Controller Access Control System (TACACS) provides access
control for routers, network access servers and other networked devices through one
or more centralized servers.
TACACS is an external authentication scheme that provides verification services.
Using TACACS, VPN-1 forwards authentication requests by remote users to the
TACACS server. The TACACS server, which stores user account information,
authenticates users. The system supports physical card key devices or token cards
and Kerberos secret key authentication. TACACS encrypts the username, password,
authentication services and accounting information of all authentication requests to
ensure secure communication.
For additional information on configuring TACACS, refer to: “Configuring a VPN-1
Gateway to use TACACS+” on page 68.
Undefined
The authentication scheme for a user can be defined as undefined. If a user with
an undefined authentication scheme is matched to a Security Rule with some form
of authentication, access is always denied.
Chapter 2
Authentication
36
The VPN-1 Solution for Authentication
Authentication Methods
In This Section
Introduction to Authentication Methods
page 37
User Authentication
page 37
Session Authentication
page 40
Client Authentication
page 41
Introduction to Authentication Methods
Instead of creating a security rule that simply allows or denies connections, the
firewall administrator can request that clients authenticate when they try to access
specific network resources.
There are three authentication methods available: user, client and session (for
additional information, refer to “Introduction to Authentication Methods” on
page 37). These methods differ in the services provided, the logon mechanism, and
the overall user experience. Each method can be configured to connect and
authenticate clients to the VPN-1 gateway before the connection is passed to the
desired resource (a process known as nontransparent authentication). Alternatively,
each method can be configured to connect clients directly to the target server (a
process known as transparent authentication).
This section describes how users authenticate using each authentication method.
For additional information on configuring authentication methods, refer to
“Configuring Authentication” on page 46.
User Authentication
User Authentication provides authentication for the Telnet, FTP, HTTP, and rlogin
services. By default, User Authentication is transparent. The user does not connect
directly to the VPN-1 gateway, but initiates a connection to the target server.
The following is a typical User Authentication method workflow:
1. VPN-1 intercepts the communication between the client and server.
2. VPN-1 prompts the user for a username and password.
3. If the user successfully authenticates, VPN-1 passes the connection to the
remote host. If incorrect authentication information is provided during the
allowed number of connection attempts, the connection is dropped.
37
The VPN-1 Solution for Authentication
4. The remote host prompts the user for a username and password.
Note - When configuring user objects, you can set the locations that they are allowed to
access, however, this can lead to a conflict with security rules that require some form of
authentication. For additional information, refer to: “Resolving Access Conflicts” on
page 55.
The following sections provide Telnet and FTP authentication scheme examples
using the User Authentication method.
Telnet Session Authentication
The following is an example of a Telnet session to 10.11.12.13 authentication
attempt using the User Authentication method and the Operating System Password
authentication scheme (Rlogin works in almost exactly the same way):
# telnet 10.11.12.13
Trying 10.11.12.13...
Connected to 10.11.12.13.
Escape character is ‘^]’.
Check Point FireWall-1 authenticated Telnet server running on
tower
User: fbloggs
FireWall-1 password: *******
User fbloggs authenticated by FireWall-1 authentication
Connected to 10.11.12.13
...
...
login:
FTP Session Authentication
To authenticate an FTP session to 10.11.12.13 using the user authentication
method and the Operating System Password authentication scheme:
1. Open an FTP session to 10.11.12.13:
# ftp 10.11.12.13
Connected to 10.11.12.13.
220 Check Point FireWall-1 Secure FTP server running on tower Name
(10.11.12.13:fbloggs):
2. Enter the username in the following format:
FTP user@FireWall-1 User@Destination Host
For example:
ftpuser@fbloggs@10.11.12.13
331 password: you can use password@password
Chapter 2
Authentication
38
The VPN-1 Solution for Authentication
3. Enter the FTP password followed by the Check Point password, for example:
Password: ftppass@xyz987
230-User fbloggs authenticated by FireWall-1 authentication
230-Connected to server. Logging in...
230-220 bigben ftp server (UNIX(r) System V Release 4.0) ready.
ftp>
Note - Escaping '@' signs in the username is achieved by using '@@'. For example, if the FTP
username is in the form of user@domain, the format of the username will be:
user@@domain@FireWall-1 User@Destination Host
4. Log in using the following user command:
ftp> user anonymous
331 Anonymous access allowed, send identity (e-mail name) as
password.
Password: fbloggs@checkpoint.com
230 Anonymous user logged in.
ftp>
Timeout Considerations for User Authentication of HTTP
In HTTP user authentication, the web browser automatically provides the password
to the server for each connection, which raises special security considerations when
using User Authentication for HTTP with one-time passwords.
To avoid forcing users with one-time passwords to generate a new password for
each connection, the HTTP Security server extends the validity of the password for
the time period defined by the User Authentication session timeout option in the
Authentication page of the Check Point Gateway window. This ensures that users of
one-time passwords do not have to reauthenticate for each request during this time
period.
To enhance security, you may want to require users to reauthenticate for certain
types of requests. For example, you can specify that every request to a specific
HTTP server requires a new password or that requests that change a server’s
configuration require a new password. To set reauthentication parameters, redefine
the Reauthentication options in the HTTP Server definition of the Global Properties >
FireWall > Security Server page.
For additional information on configuring User Authentication, refer to “Configuring
User Authentication” on page 48.
39
The VPN-1 Solution for Authentication
Session Authentication
Session Authentication can be used for any service, however, a Session
Authentication agent is required to retrieve a user’s identity. The Session
Authentication agent is normally installed on the authenticating client, whereby the
person who initiates the connection to the destination host, supplies the
authentication credentials. Session authentication requires an authentication
procedure for each connection, however, the Session Authentication agent can also
be installed on the destination machine, or on some other machine in the network,
thereby allowing the user at that machine to provide the username and password.
Figure 2-9 shows the Session Authentication Login window. After typing the
username, the user is prompted to provide a password.
Figure 2-9 Session Authentication Login Window
The following is a typical Session Authentication workflow:
1. The user initiates a connection directly to the server.
2. VPN-1 intercepts the connection.
3. The Session Authentication agent challenges the user for authentication data
and returns this information to VPN-1.
4. If the authentication is successful, VPN-1 allows the connection to pass
through the gateway and continue to the target server.
For information on configuring Session Authentication and the Session
Authentication agent, see “Configuring Session Authentication” on page 49.
Note - When configuring user objects, you can set the locations that they are allowed to
access. This can lead to conflicts with security rules that require a form of authentication.
For additional information, refer to “Resolving Access Conflicts” on page 55.
Chapter 2
Authentication
40
The VPN-1 Solution for Authentication
Client Authentication
In This Section
Client Authentication and Sign On Overview
page 41
Manual Sign On
page 42
Wait Mode
page 44
Partially Automatic Sign On
page 44
Fully Automatic Sign On
page 44
Agent Automatic Sign On
page 45
Single Sign On
page 45
Client Authentication and Sign On Overview
Client Authentication can be used to authenticate any service. It enables access
from a specific IP address for an unlimited number of connections. The client user
performs the authentication process, but it is the client machine that is granted
access. Client Authentication is less secure than user authentication because it
permits access for multiple users and connections from authorized IP addresses or
hosts. Authorization is performed on a per machine basis for services that do not
have an initial login procedure. The advantages of Client Authentication are that it
can be used for an unlimited number of connections, for any service, and is valid
for any length of time.
Note - When configuring user objects, you can set the locations that users can access,
however, this can cause problems with security rules that require some form of
authentication. For additional information, refer to “Resolving Access Conflicts” on
page 55.
41
The VPN-1 Solution for Authentication
Client Authentication works with all sign on methods. Table 2-9 shows how
different sign on methods provide choice when selecting an authentication method
for authenticated and other services. For sign on methods other than Manual Client
Authentication, the VPN-1 gateway is transparent to the users and they
authenticate directly to the destination host.
Table 2-9
Client Authentication Sign On Methods
Client
Authentication
Sign On Method
Authentication Method for
authenticated services:
Telnet, FTP, HTTP, RLOGIN
Authentication Method for
other services
Manual
Telnet to port 259 on gateway
HTTP to port 900 on gateway
Telnet to port 259 on gateway
HTTP to port 900 on gateway
Partially
automatic
User Authentication
Not available
Fully automatic
User Authentication
Session Authentication
Agent automatic
Session Authentication
Session Authentication
Single Sign on
UserAuthority
UserAuthority
The following are the two Client Authentication sign on options:
•
Standard Sign on: Enables users to access all services permitted by the rule
without authenticating for each service.
•
Specific Sign on: Enables users to access only the services that they specify
when they authenticate, even if the rule allows more than one service. If the
user wants to use another service, they must reauthenticate for that specific
service.
At the end of an authentication session, the user can sign off. When a user signs
off, they are disconnected from all services and the remote host.
Manual Sign On
Manual Sign On is available for any service that is specified in the Client
Authentication rule. The user must first connect to the gateway and authenticate in
one of the following two ways:
1. Through a Telnet session to the gateway on port 259.
2. Through an HTTP connection to the gateway on port 900 and a web browser.
The requested URL must include the gateway name and the port number, for
example, http://Gateway:900.
Chapter 2
Authentication
42
The VPN-1 Solution for Authentication
The following example shows Client Authentication using a Standard Manual Sign
On method. In this example, before opening a connection to the destination host,
the user fbloggs first authenticates to london, the VPN-1 gateway:
tower 1% telnet london 259
Trying 191.23.45.67 ...
Connected to london.
Escape character is '^]'.
CheckPoint FireWall-1 Client Authentication Server running on
london
Login: fbloggs
FireWall-1 Password: ********
User authenticated by FireWall-1 auth.
Choose:
(1) Standard Sign On
(2) Sign Off
(3) Specific Sign On
Enter your choice: 1
User authorized for standard services (1 rules)
Connection closed by foreign host.
The following example shows Client Authentication using a Specific Manual Sign
On method. In this example, two services are specified: rstat and finger (each
one to a different host).
tower 3% telnet london 259
Trying 191.23.45.67 ...
Connected to london.
Escape character is '^]'.
CheckPoint FireWall-1 Client Authentication Server running on
london
Login: jim
FireWall-1 Password: ********
User authenticated by Internal auth.
Choose:
(1) Standard Sign On
(2) Sign Off
(3) Specific Sign On
Enter your choice: 3
Service: rstat
Host: palace
Client Authorized for service
Another one (Y/N): Y
Service: finger
Host: thames
Client Authorized for service
Another one (Y/N): n
Connection closed by foreign host.
43
The VPN-1 Solution for Authentication
Wait Mode
Wait mode is a Client Authentication feature for Manual Sign On when the user
initiates a client authenticated connection with a Telnet session on port 259 on the
gateway.
Wait mode eliminates the need to open a new Telnet session in order to sign off
and withdraw client authentication privileges. In Wait mode, the initial Telnet
session connection remains open so long as client authentication privileges remain
valid. Client authentication privileges are withdrawn when the Telnet session is
closed.
VPN-1 keeps the Telnet session open by pinging the authenticating client. If for
some reason the client machine stops running, VPN-1 closes the Telnet session and
client authentication privileges from the connected IP address are withdrawn.
Enable Wait mode works only with client authentication rules that specify Standard
Sign On. In Enable Wait mode, client authentication rules that require Specific
Sign On are not applied.
Partially Automatic Sign On
Partially Automatic Sign On is available for authenticated services (Telnet, FTP,
HTTP and RLOGIN) only if they are specified in the client authentication rule. If
the user attempts to connect to a remote host using one of the authenticated
services, they must authenticate with User Authentication. When using Partially
Automatic Client Authentication, ensure that port 80 is accessible on the gateway
machine.
Fully Automatic Sign On
Fully Automatic Sign On is available for any service only if the required service is
specified in the client authentication rule. If the user attempts to connect to a
remote host using an authenticated service (Telnet, FTP, HTTP, and RLOGIN), they
must authenticate with User Authentication. If the user attempts to connect to a
remote host using any other service, they must authenticate through a properly
installed Session Authentication agent. When using Fully Automatic Client
Authentication, ensure that port 80 is accessible on the gateway machine.
Chapter 2
Authentication
44
The VPN-1 Solution for Authentication
Agent Automatic Sign On
Agent Automatic Sign On is available only if the required service is specified in the
Client Authentication rule, and the Session Authentication agent is properly
installed.
If a user attempts to connect to a remote host using any service, they must
authenticate through a Session Authentication agent.
Single Sign On
Single Sign On is available for any service only if the required service is specified
in the Client Authentication rule and UserAuthority is installed.
Single Sign On is a Check Point address management feature that provides
transparent network access. VPN-1 consults the user IP address records to
determine which users are logged on to any given IP address. When a connection
matches a Single Sign On enabled rule, VPN-1 queries UserAuthority with the
packet's source IP. UserAuthority returns the name of the user who is registered to
the IP. If the user's name is authenticated, the packet is accepted, if not, it is
dropped.
45
Configuring Authentication
Configuring Authentication
In This Section
Creating Users and Groups
page 46
Configuring User Authentication
page 48
Configuring Session Authentication
page 49
Configuring Client Authentication
page 54
Configuring Authentication Tracking
page 60
Configuring a VPN-1 Gateway to use RADIUS
page 60
Granting User Access Using RADIUS Server Groups
page 63
Associating a RADIUS Server with a VPN-1 Gateway
page 65
Configuring a VPN-1 Gateway to use SecurID
page 66
Configuring a VPN-1 Gateway to use TACACS+
page 68
Configuring Policy for Groups of Windows Users
page 69
Creating Users and Groups
Authentication rules are defined by user groups rather than individual users.
Therefore, you must first define users and then add them to groups in order to
define authentication rules. You can define users using the VPN-1 proprietary user
database or using an LDAP server. For details on incorporating LDAP, refer to
SmartDirectory (LDAP) and User Management in the SmartCenter Administration
Guide.
The following procedure describes how to create a group, create VPN-1 users using
a template, add users to the group and install user information in the database. For
additional information on creating users and groups, refer to the SmartCenter
Overview in the SmartCenter Administration Guide.
Creating User Groups
To create a user group:
1. Select User Groups from the Users and Administrators tab of the Objects tree.
2. Right-click and select New Group.... The Group Properties window opens.
3. Assign the group a Name.
4. To add users to the group, refer to “Creating Users” on page 47.
Chapter 2
Authentication
46
Configuring Authentication
Creating a User Template
To create a user template:
1. Select the Users from the Users and Administrators tab of the Objects tree.
2. In the Templates branch, right-click and select New Template.... The User
Template Properties window opens.
3. Assign the template a name.
4. In the Groups tab, add the user template to all of the groups to which users
based on this template must belong.
5. In the Authentication tab, select the appropriate authentication scheme for the
user.
6. In the remaining tabs, enter the required properties of the user template.
Once you create a template, any user that you create based on a given template
inherits that template’s properties, including membership in groups. If you modify
a template’s properties, those changes will only affect future users created using
that template. Users previously created using that template are not affected.
Creating Users
To create users:
1. In the Users branch of the objects tree, right-click and select the template on
which the new user’s properties are to be based. The User Properties window
opens.
2. Enter the user data. You can change the properties that the user inherited from
the template for that user only without changing the template.
Installing User Information in the Database
Users and groups can be installed separately from the Rule Base, meaning that you
can update users and groups without reinstalling the Rule Base.
To install the user database:
•
47
From the SmartDashboard menu, select Policy > Install Database....
Configuring Authentication
Configuring User Authentication
To configure user authentication:
1. Configure authentication for required users and groups and install the user
database (for additional information, refer to: “Creating Users and Groups” on
page 46).
2. Define a user authentication access rule as follows:
a. Right-click in the Source column, select Add User Access... and then select
the group.
b. To restrict the location of authenticating users, select Restrict To and the
host, group of hosts, network or group of networks that users can access in
the Location section of the same window.
c. In the Service field, select the services you wish to authenticate.
d. In the Action column, select User Auth. Table 2-10 shows an HTTP User
Authentication Rule.
Table 2-10
User Authentication Rule for HTTP and FTP
SOURCE
DESTINATION
VPN
SERVICE
ACTION
Alaska_Users@Any
Alaska_LAN
Any
Traffic
HTTP
FTP
User Auth
3. Double-click the Action column to edit the User Authentication Action Properties.
4. If required, adjust the User Authentication session timeout from the
Authentication page of the VPN-1 gateway object.
5. Install the security policy.
The Importance of Rule Order in User Authentication
When defining user authentication rules for Telnet, FTP, HTTP, and RLOGIN
services, if there are other non-authentication rules that use these services, ensure
that the user authentication rule is located last amongst these rules.
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Configuring Authentication
Configuring Session Authentication
To configure session authentication:
1. If using the Session Authentication Agent, install and configure it for all
machine desktops with Session Authentication enabled (for additional
information, refer to “Installing and Configuring the Session Authentication
Agent” on page 50).
2. Configure the required users and groups for authentication, and install the user
database (for additional information, refer to “Creating Users and Groups” on
page 46).
3. From the Authentication page, edit the Check Point Gateway object that
represents the gateway and enable the required authentication schemes. The
gateway must support all of the user defined authentication schemes. For
example, if some users must provide a Check Point password, and others
RADIUS authentication, select both schemes.
4. Define a Session Authentication access rule by doing the following:
a. Right-click in the Source column, select Add User Access... and then the
group. Do not close the window.
b. To restrict the location of authenticating users, in the Location section of
the same window, select Restrict To and the host, group of hosts, network or
group of networks that users can access.
c. In the Service field, select the services you want to authenticate.
d. In the Action column, select Session Auth. Table 2-11 shows a typical
Session Authentication Rule.
Table 2-11
Session User Authentication Rule for HTTP and FTP
SOURCE
DESTINATION VPN
SERVICE
ACTION
Alaska_Users@Any
Alaska_LAN
HTTP
FTP
Session
Auth
Any Traffic
5. Double-click the Action column to edit the User Authentication Action Properties.
6. If required, adjust the Failed Authentication Attempts settings for Session
Authentication in the Authentication page of the Global Properties.
7. Install the security policy.
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Configuring Authentication
Installing and Configuring the Session Authentication
Agent
To install and configure the Session Authentication Agent:
1. Install the Session Authentication agent from the CD-ROM. The Session
Authentication agent is normally installed on the authenticating client, in which
case users who want to connect to the destination host provide the
authentication credentials. The Session Authentication agent can also be
installed on the destination machine or on some other machine in the network.
In that case, the user at the machine on which the Agent is installed is
prompted to provide authentication credentials.
2. On Windows machines, double-click the Session Authentication agent icon in
the system tray. The FireWall-1 Session Authentication window (Figure 2-10)
opens.
Figure 2-10 FireWall-1 Session Authentication Window
3. Click Configure. The Configuration window opens and displays the Passwords tab
(Figure 2-11). In the Passwords tab, specify how often the user is prompted to
provide their password. One-time passwords (such as SecurID) cannot be
cached.
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Configuring Authentication
Figure 2-11 Configuration Window — Passwords Tab
4. Select one of the following options:
•
Every request: The user is prompted for a password each time that VPN-1
requests authentication. Each time that the user initiates a session for
which a Session Authentication Rule applies, the user is prompted for the
password. No password caching occurs.
•
Once per session: The user is prompted for the password once per Session
Authentication Agent session. Once the user provides the password, the
Session Authentication agent caches the password indefinitely. This option
cannot be used with one-time passwords. If the Session Authentication
Agent session is closed and then restarted, the user must provide the
password again.
•
After ... minutes of inactivity: Similar to the Once per session option, however,
the user is prompted again for the password if there has been no
authentication request over a specified time interval.
5. In the Configuration window, select the Allowed FireWall-1 tab. The Allowed
Firewall-1 tab displays (Figure 2-12). From the Allowed FireWall-1 tab you can
specify the VPN-1 gateways for which the Session Authentication agent can
provide authentication services.
51
Configuring Authentication
Figure 2-12 Configuration window — Allowed FireWall-1 Tab
6. Select one of the following options:
•
Any IP Address: The Session Authentication agent can provide
authentication services for any VPN-1 gateway.
•
IP Address: The Session Authentication agent can provide authentication
services for only a VPN-1 gateway running on a user-specified IP address
(you can specify up to three IP addresses).
7. In the Configuration window, select the Options tab. The Options tab displays
(Figure 2-13). From the Options tab you can specify whether to allow clear
passwords and to resolve addresses.
Figure 2-13 Configuration Window — Options Tab
Select the appropriate option and click OK.
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Configuring Authentication
Starting the Session Authentication Agent
To start the Session Authentication Agent:
•
53
From the Windows system tray, select the minimized Session Authentication
Agent icon. The user can now configure the Session Authentication Agent
and/or receive authentication requests from a VPN-1 gateway.
Configuring Authentication
Configuring Client Authentication
In This Section
Performing Basic Client Authentication Configuration
page 54
Enabling Client Authentication Wait Mode
page 55
Resolving Access Conflicts
page 55
Authorizing All Standard Sign On Rules
page 56
Changing the Client Authentication Port Number
page 57
Allowing Encrypted Client Authentication (HTTPS Connections)
page 58
Performing Basic Client Authentication Configuration
To perform basic client authentication configuration:
1. Configure the required users and groups for authentication and install the user
database (for additional information, refer to “Creating Users and Groups” on
page 46).
2. From the Authentication page, edit the Check Point Gateway object that
represents the VPN-1 gateway and enable the required authentication schemes.
The gateway must support all of the user defined authentication schemes. For
example, if some users must provide a Check Point password, and others
RADIUS authentication, select both schemes.
3. Define a Client Authentication access rule as follows:
a. Right-click in the Source column, select Add User Access... and then the
group. Do not close the window.
b. To restrict the location of authenticating users, in the Location section of
the same window, select Restrict To and the host, group of hosts, network or
group of networks that users can access.
c. In the Service field, select the services you want to authenticate.
d. In the Action column, select Client Auth. Table 2-12 shows a Client
Authentication Rule for HTTP and FTP.
Table 2-12
Client Authentication Rule for HTTP and FTP
SOURCE
DESTINATION VPN
SERVICE
ACTION
Alaska_Users@Any
Alaska_LAN
HTTP
FTP
Client Auth
Any Traffic
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4. For Partially or Fully Automatic Client Authentication, ensure that port 80 is
accessible on the gateway machine.
5. Double-click in the Action column to edit the Client Authentication Action
Properties. The settings for Requires Sign On and Sign On Method are
described in “Client Authentication” on page 41.
6. Place all Client Authentication Rules above the rule that prevents direct
connections to the VPN-1 gateway (the Stealth Rule) to ensure that they have
access to the VPN-1 gateway.
7. If required, adjust the Failed Authentication Attempts settings for Client
Authentication in the Authentication page of the Global Properties window.
8. Install the security policy.
Enabling Client Authentication Wait Mode
When using Manual Sign On and the user authenticates with a Telnet session to
port 259 on the gateway, Wait mode eliminates the need to open a new Telnet
session in order to sign off and withdraw client authentication privileges.
To enable Wait mode:
1. From the Authentication page, edit the Check Point Gateway object that
represents the VPN-1 gateway and select Enable Wait Mode for Client
Authentication. In Client Authentication Wait mode, VPN-1 monitors the Telnet
connection to port 259 of the gateway by pinging the user’s host.
2. Define rules to enable pinging as follows:
•
Enable the echo-request service from the VPN-1 gateway to the user’s host.
•
Enable the echo-reply service from the user’s host to the VPN-1 gateway.
Resolving Access Conflicts
When configuring users, you can define those locations that they can access.
However, by doing so, you disallow access to all unspecified locations, which can
cause conflicts with security rules that require authentication. For example, if a
rule grants authenticated access to users from Mktg_net to Finance_net, but in the
user’s Location tab connections are only permitted within Mktg_net, VPN-1 does not
know whether to allow the authentication request when the user tries to connect to
Finance_net.
You can specify how to resolve this conflict by editing the Authentication Action
Property of the rule. You can define this property for both the Source and Destination
of the rule.
55
Configuring Authentication
To resolve access conflicts:
1. Right-click the Action field of a rule using some form of authentication and
select Edit Properties.
2. Do one of the following:
•
To apply the more restrictive access privileges specified in the rule and in
the Location tab of each user’s User Properties window, select Intersect with
User Database.
•
To allow access according to the location specified in the rule, select Ignore
User Database.
Authorizing All Standard Sign On Rules
By default, the Partially or Fully Automatic sign on methods open one rule following
successful authentication (the rule for which the sign on was initiated). For
example, if a user successfully authenticates according an automatic sign on rule,
the user can work with the services and destinations permitted only by that rule.
You can configure VPN-1 to automatically open all Standard Sign On rules
following successful authentication using Partially or Fully Automatic Sign On. If a
user successfully authenticates according to an automatic sign on rule, then all
Standard Sign On rules that define that user and source are available. The user can
then work with all of the services and destinations permitted by the relevant rules
(VPN-1 knows which user is at the client, and additional authentication is not
necessary).
To authorize all relevant Standard Sign On Rules following successful .
Partially or Fully Automatic authentication, use the GUIdbedit Database Tool to
change a setting in the VPN-1 database.
To authorize all standard sign on rules:
1. Access the GUIdbedit Database Tool from the same directory on your local drive
as where SmartConsole is installed.
2. Open GUIdbedit.
3. Search for the automatically_open_ca_rules field.
4. Set the value to true. The new value takes effect after you install the security
policy.
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Changing the Client Authentication Port Number
To change the Client Authentication port number:
1. Stop VPN-1 by running the cpstop command.
2. Modify the port number in the Manage > Service > Show > TCP Services window
for the following services:
•
To modify the port number for Telnet sign on, change the port number of
the FW1_clntauth_telnet service.
•
To modify the port number for HTTP sign on, change the port number of the
FW1_clntauth_http service.
These are special VPN-1 services provided as part of the Client Authentication
feature.
3. Use a simple text editor to edit the $FWDIR/conf/fwauthd.conf file. Change the
port number of the Client Authentication application to the same port number
defined in step 2.
4. Do one of the following:
•
For Telnet Sign On, modify the first column in the in.aclientd line.
• For HTTP Sign On, modify the first column in the in.ahclientd line.
Figure 2-14 $FWDIR/conf/fwauthd.conf File
21fwssd in.aftpd wait 0
80 fwssd in.ahttpd wait 0
513 fwssd in.arlogindwait 0
25 fwssd in.asmtpd wait 0
23 fwssd in.atelnetd wait 0
259 fwssd in.aclientd wait 259
10081 fwssd in.lhttpd wait 0
900 fwssd in.ahclientdwait 900
0 fwssd in.pingd respawn 0
0 fwssd in.asessiond respawn 0
0 fwssd in.aufpd respawn 0
0 vpn vpnd respawn 0
0 fwssd mdq respawn 0
0 xrm xrmdrespawn0-pr
Warning - Do not change anything else in these lines.
57
Configuring Authentication
5. Ensure that there is no rule that blocks the connection to the new port.
6. Restart VPN-1 by running the cpstart command.
For additional information on configuring Client Authentication, refer to
“Configuring Client Authentication” on page 54.
Allowing Encrypted Client Authentication (HTTPS
Connections)
To configure Encrypted Client Authentication:
1. Run the cpstop command on the VPN-1 gateway.
2. Edit the fwauthd.conf file in the $FWDIR/conf directory by changing the line:
900
fwssd
in.ahclientd
wait
900
fwssd
in.ahclientd
wait
900 ssl:defaultCert
to:
900
Note - defaultCert is a nickname on the Certificate List on the VPN-1 gateway. To check
the nickname of your gateway, open the VPN page of the Gateway Properties window and
see the Certificates List.
3. Save and close the file.
4. Run cpstart.
5. Open SmartDashboard.
6. Create the following Rule (Table 2-13):
Table 2-13
Source
Destination
Service
Action
User_group@Any
Internal
server
https
Client Auth
(Partially
automatic
or Manual mode)
Note - This Rule also permits HTTPS traffic between the client and the Web server
following successful authentication.
7. Install the policy.
8. In the client's browser, do the following:
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58
Configuring Authentication
a. Type the URL addresshttps://<FireWall-1_name_or_IP_address>:900.
b. Click Yes to trust the VPN-1 gateway certificate.
c. Type the VPN-1 user name.
d. Click OK.
e. Click Yes.
f.
Type the VPN-1 password.
g. Click Submit.
h. Type the URL address: https://<Internal_Web_Server_IP_address>.
i.
Click Yes.
You are now authenticated both to the VPN-1 gateway and to your internal Web
server.
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Configuring Authentication
Configuring Authentication Tracking
Successful and unsuccessful authentication attempts can be monitored in
SmartView Tracker or using other tracking options, for example, email and alerts.
Authentication tracking can be configured for the following types of authentication
attempts:
•
Failed authentication attempts: Can be tracked for all forms of authentication.
To track failed authentication attempts:
•
•
In the Authentication page of a gateway object, set the Authentication Failure
Track property to define the tracking option when authentication failures
occur.
Successful authentication attempts: Can be tracked for Client Authentication.
To track successful authentication attempts:
1. In the Client Authentication Action Properties window, set the Successful
Authentication Tracking property to define the tracking option for all
successful Client Authentication attempts.
2. To set this option, right-click in the Action column of the Client
Authentication rule. The default setting is Log.
•
All Authentication attempts: Can be tracked for all forms of authentication.
To track all authentication attempts:
•
Select an option in the Track column of any rule that uses some form of
authentication. The Set by Rule tracking option can only be added to the
tracking policy set in the gateway object. For example, if the gateway object
is set to log all failed authentication attempts, setting a rule to None has no
effect and failed authentication attempts are still logged in SmartView
Tracker. However, setting the rule to Alert causes an Alert to be sent for
each failed authentication attempt.
Note - Authentication failure tracking for Check Point firewall versions prior to NG is
defined by the Authentication Failure Track property in the Authentication page of the
Global Properties window.
Configuring a VPN-1 Gateway to use RADIUS
To configure a VPN-1 gateway to use RADIUS authentication:
1. In SmartDashboard, create a RADIUS Host object by selecting Manage >
Network Objects > New > Node > Host....
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Configuring Authentication
2. Name the Host object and assign it an IP address.
3. Create a RADIUS Server object by selecting Manage > Server and OPSEC
Applications > New…> RADIUS…, and configure the following:
a. Name the RADIUS Server object.
b. Associate the RADIUS Server object with the RADIUS Host object created
in step 1.
c. Assign the Service by selecting either the RADIUS on port 1645 or
NEW-RADIUS on port 1812 service. (The default setting is RADIUS, however
the RADIUS standards group recommends using NEW-RADIUS, because port
1645 can conflict with the datametrics service running on the same port.)
d. Assign the same Shared Secret that you configured on the actual RADIUS
server.
e. Select either RADIUS Ver. 1.0 Compatible, which is RFC 2138 compliant, or
RADIUS Ver. 2.0 Compatible, which is RFC 2865 compliant.
f.
Assign the RADIUS server’s Priority if you are employing more than one
RADIUS Authentication server.
g. Click OK.
4. Right-click the gateway object and select Edit > Authentication.
5. Enable RADIUS authentication.
6. Define a user group by selecting Manage > Users & Administrators > New > User
Group (for example, RADIUS_Users).
7. Enable RADIUS authentication for VPN-1 users by selecting Manage > Users
and Administrators > New > User by Template > Default..
8. Enable RADIUS authentication for users without VPN-1 user accounts by
creating an External User Profile. Select Manage > Users and Administrators >
New > External User Profile > Match all users... or Match by domain.... To support
more than one external authentication scheme, define your External User
Profiles with the Match By Domain setting.
9. For all User Profiles and Templates, configure the following:
a. In the General tab, type the default login name for the RADIUS server.
(When configuring Match all users as an External User Profile, the name
“generic*” is automatically assigned.)
b. In the Personal tab, adjust the Expiration Date.
c. In the Authentication tab, select RADIUS from the drop-down list.
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Configuring Authentication
d. In the Groups tab, add the User Profile to the RADIUS group.
10. Verify that communication between the firewall and the RADIUS server are not
NATed in the Address Translation Rule Base.
11. Save, verify, and install the policy.
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Granting User Access Using RADIUS Server Groups
VPN-1 gateway enables you to control access for authenticated RADIUS users,
based on the administrator’s assignment of users to RADIUS groups. These groups
are used in the Security Rule Base to restrict or grant access to users to specific
resources. Users are unaware of the groups to which they belong.
To use RADIUS groups, you must define a return attribute in the RADIUS user
profile of the RADIUS server. This attribute is returned to the VPN-1 gateway and
contains the group name (for example, RAD_<group to which the RADIUS users
belong>) to which the users belong. Although other RADIUS attributes can be used,
by default the Class attribute is used (IETF RADIUS attribute number 25).
To grant access using RADIUS server groups:
1. On the VPN-1 gateway, follow step 1 to step 4 in “Configuring a VPN-1
Gateway to use RADIUS” on page 60.
2. Create an External User Profile by selecting Manage > Users and Administrators
> New... > External User Profile > Match all users.... This is the generic* user.
3. In the Authentication tab, select RADIUS as the Authentication Scheme and then
select the created RADIUS server (not the node) from the drop-down list.
4. Define the required RADIUS user groups by selecting Manage > Users &
Administrators > New > User Group. The name of the group must be in the
format: RAD_<group to which the RADIUS users belong>. Ensure the group is
empty.
5. Create the required Rule Base rules to allow access to RADIUS users.
6. Save the changes, and exit SmartDashboard.
7. Run cpstop on the SmartCenter server.
8. On the SmartCenter server, use the Graphical Database Tool (GUIdbEdit) to
change the value of the add_radius_groups attribute from false to true.
9. Run cpstart on the SmartCenter server.
10. Install the policy.
11. On the RADIUS server, modify the RADIUS users to include a class RADIUS
attribute on the users Return list that corresponds to the user group that they
access.
63
Configuring Authentication
To use a different attribute instead of the class attribute, do one of the
following:
•
On the VPN-1 gateway, use GUIdbEdit to modify the value of the
firewall_properties attribute radius_groups_attr to the new RADIUS
attribute. On the RADIUS server, ensure that you use the same RADIUS
attribute (on the users' Return list that corresponds to the Firewall user
group that they access).
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Configuring Authentication
Associating a RADIUS Server with a VPN-1
Gateway
You can associate users with the Radius authentication server in the User Properties
Authentication tab. You can also associate a gateway with a Radius server so that
this overrides the User to Radius server association. This is performed by editing
the VPN-1 database using the dbedit command.
To associate one or more Radius servers to a gateway:
1. Run the dbedit command:
modify network_objects <gw obj> radius_server servers:<radius obj>
2. To switch off the Radius to VPN-1 association so that the user always
authenticates to the Radius server specified in the User Properties Authentication
tab, switch off another attribute in the VPN-1 database by running the dbedit
command:
modify users <user obj> use_fw_radius_if_exist false
65
Configuring Authentication
Configuring a VPN-1 Gateway to use SecurID
To configure a VPN-1 gateway to use SecurID:
1. Generate and copy the sdconf.rec file from the ACE/Server to:
•
/var/ace/sdconf.rec on UNIX, Linux or IPSO
•
%SystemRoot%\System32\sdconf.rec on Windows
2. In SmartDashboard, right-click the gateway object and select Edit >
Authentication page.
3. Enable SecurID authentication.
4. Define a user group by selecting Manage > Users & Administrators > New > User
Group (for example, SecurID_Users).
5. Enable SecurID authentication for VPN-1 users by selecting Manage > Users and
Administrators > New > User by Template > Default..
6. Enable SecurID authentication for users without VPN-1 user accounts by
creating an External User Profile. Select Manage > Users and Administrators >
New > External User Profile > Match all users... or Match by domain.... If you
support more than one external authentication scheme, set up your External
User Profiles with the Match By Domain setting.
7. For all User Profiles and Templates, configure the following:
a. In the General tab, enter the default login name for the ACE/Server. (When
configuring Match all users as an External User Profile, the name “generic*”
is automatically assigned).
b. In the Personal tab, change the Expiration Date.
c. In the Authentication tab, select SecurID from the drop-down list.
d. In the Groups tab, add the User Profile to the SecurID group.
8. Verify that communication between the firewall and the ACE/Server are not
NATed in the Address Translation Rule Base.
9. Save, verify, and install the policy.
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Configuring Authentication
When a VPN-1 gateway has multiple interfaces, the SecurID agent in VPN-1
sometimes uses the wrong interface IP to decrypt the reply from the ACE/Server,
and authentication fails.
To overcome this problem, place a new text file, named sdopts.rec, in the
same directory as sdconf.rec. The file should contain the CLIENT_IP=<ip> line,
where <ip> is the primary IP address of VPN-1, as defined on the ACE/Server.
This is the IP address of the interface to which the server is routed.
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Configuring Authentication
Configuring a VPN-1 Gateway to use TACACS+
To configure a VPN-1 gateway to use TACACS+:
1. In SmartDashboard, create a TACACS Host object by selecting Manage >
Network Objects > New > Node > Host...
2. Name the Host object and assign it an IP address.
3. Create a TACACS server by selecting Manage > Server and OPSEC Applications >
New…> TACACS…, and configure the following:
a. Name the TACACS server object.
b. Associate the TACACS server object with the TACACS Host object created in
step 1.
c. Select the Type of TACACS you want to run. (The default is TACACS, but
TACACS+ is recommended).
d. Assign the Service. Match the TACACS service (UDP or TCP) to the Type
selected in step c.
4. Right-click the gateway object and select Edit > Authentication.
5. Enable TACACS authentication.
6. Define a user group by selecting Manage > Users & Administrators > New > User
Group (for example, TACACS_Users).
7. Enable TACACS authentication for VPN-1 users by selecting Manage > Users
and Administrators > New > User by Template > Default..
8. Enable TACACS authentication for users without VPN-1 user accounts by
creating an External User Profile. Select either Manage > Users and
Administrators > New > External User Profile > Match all users... or Match by
domain.... If more than one external authentication scheme is supported, set up
your External User Profiles using the Match By Domain setting.
9. For all User Profiles and Templates, configure the following:
a. In the General tab, enter the default login name for the TACACS Server.
(When configuring Match all users as an External User Profile, the name
“generic*” is automatically assigned).
b. In the Personal tab, change the Expiration Date.
c. In the Authentication tab, select TACACS from the drop-down list.
d. In the Groups tab, add the User Profile to the TACACS group.
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10. Verify that communication between the firewall and the TACACS server is not
NATed in the Address Translation Rule Base.
11. Save, verify, and install the policy.
Configuring Policy for Groups of Windows Users
You can create policy rules for groups of users that are not defined on the
SmartCenter server, but are defined either on the gateway’s host (a Windows
machine) or in the Windows machine’s trusted domain.
To configure policy for groups of Windows users:
1. Enable this feature using the Graphical Database Tool (GUIdbEdit).
2. Change the value of the add_nt_groups attribute to true. (This attribute is
located under the firewall_properties object in the properties table.)
3. Ensure that the user belongs to a Windows user group.
4. In the SmartDashboard, create a user group with the name: Windows_<Windows
user group which the user belongs to>. The group may be empty.
5. Define a Generic User Profile for each user that uses an operating system
password as its authentication scheme.
69
Connectivity
This section describes how to give internal users and resources unrestricted yet
secure connectivity across the gateway.
3
Chapter
Network Address Translation
(NAT)
In This Chapter
The Need to Conceal IP Addresses
page 100
Check Point Solution for Network Address Translation
page 101
Planning Considerations for NAT
page 114
Configuring NAT
page 116
Advanced NAT Configuration
page 122
99
The Need to Conceal IP Addresses
The Need to Conceal IP Addresses
In an IP network, each computer is assigned a unique IP address that defines both
the host and the network. Many computers in an organization have private,
non-routable IP addresses, but also require access to the Internet. Normally, it is
impossible to give each computer an Internet-routable IP address due to the lack of
available public IP addresses and administrative constraints.
IPv4 (the current version of IP) provides only 32 bits of address space. This makes
available IP addresses scarce since most addresses have already been assigned.
Internet Service Providers usually allocate only one or a few addresses at a time.
Larger companies may purchase several addresses for use, but purchasing
addresses for every computer on a network is not practical for most companies.
Even if additional public IP addresses become available, changing the addresses of
every machine in a large network would be both labor intensive and time
consuming.
Whether computers have routable or non-routable addresses, the administrator may
want to conceal their real addresses for security reasons, for example, to ensure
that addresses cannot be seen from outside the organization or from other parts of
the same organization. A network’s internal addresses contains the topology of the
network and, therefore, hiding this information greatly enhances security.
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Check Point Solution for Network Address Translation
Check Point Solution for Network Address
Translation
In This Section
Public and Private IP addresses
page 101
NAT in VPN-1
page 102
Static NAT
page 103
Hide NAT
page 104
Automatic and Manual NAT Rules
page 105
Automatic Hide NAT for Internal Networks
page 106
Address Translation Rule Base
page 107
Bidirectional NAT
page 108
Understanding Automatically Generated Rules
page 109
Port Translation
page 111
NAT and Anti-Spoofing
page 111
Routing Issues
page 111
Disabling NAT in a VPN Tunnel
page 113
Public and Private IP addresses
Public IP addresses are those that are routable on the Internet. RFC 1918
documents private address spaces that can be used on internal networks and do
not have hosts directly connected to the Internet. The Internet Assigned Numbers
Authority (IANA) has set aside the following three blocks of IP addresses for
internal (private) network use:
•
Class A network numbers: 10.0.0.0–10.255.255.255
•
Class B network numbers: 172.16.0.0–172.31.255.255
•
Class C network numbers: 192.168.0.0–192.168.255.255
When an enterprise employs an intranet using private addresses, a VPN-1 NAT
gateway connects the intranet to the Internet. The Global Properties > Non Unique IP
Address Ranges page specifies the address ranges that VPN-1 considers private
(non-unique).
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Check Point Solution for Network Address Translation
NAT in VPN-1
Network Address Translation (NAT) involves replacing one IP address with another.
NAT can change both the source and destination address inside the packet. This
means that a packet that is sent from the internal (protected) side to the external
(unprotected) side of the firewall appears to the destination as if it came from a
different address, and the packet that is sent from the external to the internal side
of the firewall arrives at the correct address.
VPN-1 supports two kinds of NAT:
•
Static NAT: Each private address is translated to a corresponding public
address. In a typical Static NAT scenario, with a number of machines in an
internal network, the address of each machine is translated to a different public
IP address. It is a many-to-many translation. Static NAT allows machines on
both sides of the VPN-1 gateway to initiate connections, for example, so that
internal servers can be made available externally.
•
Hide NAT: A single public address is used to represent multiple computers with
private addresses on the internal network. Hide NAT is a many-to-one
translation. Hide NAT allows connections to be initiated only from the protected
side of the VPN-1 gateway.
NAT can be performed on Check Point network objects, nodes, networks, address
ranges, and dynamic objects. NAT can be defined either automatically through the
network object, by automatically adding rules to the Address Translation Rule Base,
or manually by defining rules in the Address Translation Rule Base.
Manually creating NAT Rules adds extra flexibility. For example, in addition to
translating IP addresses, you can translate the service or the destination port
numbers. Port number translation is a type of Static NAT, in which one port number
is translated to another port number.
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Check Point Solution for Network Address Translation
Static NAT
Static NAT translates each private address to a corresponding public address.
Static NAT on a node translates the private address of the node to a public address.
Static NAT on a network or address range translates each IP address in the network
or range to a corresponding public IP address, starting from the defined Static IP
address.
In Figure 3-1, the address range 10.1.1.2 to 10.1.1.10 is hidden behind the NAT
range 192.168.0.2-192.168.0.11. The diagram shows a connection that originates
at 10.1.1.3, and the source and destination translation of the original and reply
packet.
Figure 3-1 Static NAT on an Address Range
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Check Point Solution for Network Address Translation
Hide NAT
The NAT gateway makes it possible to share a single public address with multiple
computers that have private addresses on your intranet. The Internet is unaware of
the division you have created between the Internet and your intranet, and treats
your multiple computer connection as a single connection.
Hide NAT allows only connections that originate on the internal network. This lets
an internal host initiate a connection to both inside and outside the intranet,
however, a host outside the network cannot initiate a connection to an internal
host.
The Hide Address is the address behind which the internal network, address range
or node is hidden. You can opt to hide the internal address(es) either:
•
Behind a virtual IP address, which is a public (routable) IP address that does
not belong to any real machine, or
•
Behind the IP address of the VPN-1 interface through which the packet is
routed out of (formerly known as “Hiding behind IP address 0.0.0.0”).
In Figure 3-2, the address range 10.1.1.2 to 10.1.1.10 is hidden behind the
address of the external VPN-1 interface (192.168.0.1). The diagram shows a
connection that originates at 10.1.1.3, and the source and destination translation
of the original and reply packet.
Figure 3-2 Hide NAT on An Address Range
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Check Point Solution for Network Address Translation
How Hide NAT Works
In Hide mode, the source port numbers of the packets are modified. When return
packets enter a firewall, VPN-1 use the port number to determine to which internal
machines the packets are destined. Port numbers are dynamically assigned from
two pools of numbers: 600 to 1023 and 10,000 to 60,000.
Port numbers are normally assigned from the second pool. The first pool is used for
only three services: rlogin (destination port 512), rshell (destination port 513) and
rexec (destination port 514). If the connection uses one of these services, and the
original source port is less than 1024, then a port number is assigned from the
first pool. This behavior is configurable.
VPN-1 keeps track of the port numbers assigned, so that the original port number
is correctly restored for return packets and a port number that is currently in use is
not assigned again to a new connection.
Hide NAT has a capacity of 50,000 connections per server. The Hide NAT capacity
limit is only reached if more than 50,000 connections from Hide NATed internal
clients are simultaneously directed at a single server on the unprotected side of the
VPN-1 gateway—a highly unlikely scenario.
Automatic and Manual NAT Rules
NAT can be defined automatically through the network object (node, network or
address range). When you define NAT this way, rules are automatically added to the
Address Translation Rule Base.
You can manually specify NAT rules by adding or editing NAT rules in the Address
Translation Rule Base. VPN-1 validates manual NAT rules, helping to avoid
mistakes in the setup process. Creating manual NAT Rules gives maximum control
over the way NAT functions. You can specify the source, destination and service
separately for both the original and the translated packet.
When creating Manual NAT rules, you must define the translated network objects in
addition to the original objects.
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Check Point Solution for Network Address Translation
Automatic Hide NAT for Internal Networks
You can use Hide NAT to allow Internet access for large and complex internal
networks that contain many subnets, not all of which may be known.
Regular Hide NAT requires that all internal network addresses that need to be
NATed must be specified, even though this may be impractical.
If this is the case, you can specify automatic Hide NAT for all internal networks,
which means that every connection entering from an internal interface and exiting
through an external gateway interface (as defined in the Topology page of the
gateway object) is NATed behind the external gateway interface address.
Figure 3-3 shows connections from clients in internal networks initiating
connections to servers in the Internet. The source addresses of internal clients are
NATed to the address of the external interface, either 192.168.0.1 or 172.16.1.1,
depending on the interface from which the connection emerges.
Figure 3-3 Hide NAT Behind Gateway Interface
Note - Regular NAT rules take precedence over NAT-for-internal-networks rules.
If a connection matches both a regular NAT rule and a
NAT-for-internal-networks rule, the connection is matched to the regular NAT
rule.
Access rules must also be defined in the Rule Base.
For additional configuration information, refer to See “Configuring Automatic Hide
NAT for Internal Networks” on page 121.
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Check Point Solution for Network Address Translation
Address Translation Rule Base
Figure 3-4 shows the Address Translation Rule Base.
Figure 3-4 Address Translation Rule Base
Each rule specifies what happens to the first packet of a connection. Reply packets
travel in the opposite direction to the original packet, but are matched to the same
rule.
The Address Translation Rule Base is divided into two sections:
•
Original Packet: Specifies the conditions when the rule is applied.
•
Translated Packet: Specifies the action taken when the rule is applied.
Each section in the Address Translation Rule Base Editor is divided into Source,
Destination, and Service. The following actions are performed:
•
Translate Source under Original Packet, to Source under Translated Packet
•
Translate Destination under Original Packet, to Destination under Translated
Packet
•
Translate Service under Original Packet, to Service under Translated Packet
Rule Match Order
Rule matching in the Address Translation Rule Base follows the same principle as
in the Rule Base. When VPN-1 receives a packet belonging to a connection, it first
compares it against the first rule in the Rule Base, then the second rule, and then
the third rule, and so on. When it finds a rule that matches, it stops checking and
applies that rule.
The exception to this principle is when two automatic rules match a connection, in
which case, bidirectional NAT is applied.
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Network Address Translation (NAT) 107
Check Point Solution for Network Address Translation
Bidirectional NAT
Bidirectional NAT applies to automatic NAT rules in the Address Translation Rule
Base and allows two automatic NAT rules to match a connection. Without
bidirectional NAT, only one automatic NAT rule can match a connection.
When NAT is defined for a network object, an automatic NAT rule is generated
which performs the required translation. If there are two network objects, where
one is the source of a connection and the other is the destination, using
bidirectional NAT, both automatic NAT rules are applied and both objects are
translated.
The logic behind bidirectional NAT is:
•
If the first match of a connection is on a Manual NAT rule, no further checking
of the NAT Rule Base is performed.
•
If the first match of a connection is on an Automatic NAT rule, the rest of the
NAT Rule Base is checked, one rule at a time, to verify whether another
Automatic NAT rule matches the connection. If it finds another match, both
rules are matched and no further checking is performed.
The operation of bidirectional NAT can be tracked using the SmartView Tracker and
the NAT Rule Number and NAT Additional Rule Number fields . The additional rule
is the rule that matches the automatic translation performed on the second object
in bidirectional NAT.
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Check Point Solution for Network Address Translation
Understanding Automatically Generated Rules
NAT can be defined automatically through a network object (node, network or
address range), with rules added automatically to the Address Translation Rule
Base.
Hide NAT on a node adds one rule to the Address Translation Rule Base. It
specifies that the source address of the packet is translated for connections
originating from the node in the internal network (Source Hide Rule).
Static NAT on a node adds two rules to the Address Translation Rule Base. In
addition to the Source Hide rule, another rule specifies that for connections
originating from the external network, the Destination address of the packet is
translated (Destination Static Rule).
If NAT (Hide or Static) is performed on a network or an address range, an extra rule
is added which specifies that communication within the network or address range
is not translated (a packet sent from one machine to another in the same network
is not changed).
Example of an Automatically Generated Rule (Hide
NAT)
In the scenario displayed in Figure 3-2 on page 104, automatically defined Hide
NAT on the address range node adds two rules to the NAT Rule Base (Figure 3-5).
Figure 3-5 Automatically Generated NAT Rules for Hide NAT on an Address Range
Rule 1 states that for connections within the internal (unprotected) side of the
firewall, no NAT takes place.
Rule 2 states that for connections initiated on the internal (protected) side of the
firewall, the source address of the packets is translated to the public Hide NAT
address.
In automatic Hide NAT rules, the translated address is known as the Hiding
Address and is used on the unprotected side of the VPN-1 gateway. The actual
addresses are private addresses that are used on the protected side of the
VPN-1 gateway.
Chapter 3
Network Address Translation (NAT) 109
Check Point Solution for Network Address Translation
Example of Automatically Generated Rules (Static NAT)
In the scenario in Figure 3-1 on page 103, automatically defined Static NAT on the
node adds two rules to the NAT Rule Base (Figure 3-6).
Figure 3-6 Automatically Generated NAT Rules for Static NAT on an Address Range
Rule 1 states that for connections within the internal (unprotected) side of the
firewall, no NAT takes place. A packet sent from one machine to another in the
same network is not changed.
Rule 2 states that for packets originating from the internal (protected) side of the
firewall, source addresses are translated to valid (public) static NAT addresses.
Rule 3 states that for packets originating from the external (unprotected) side of
the firewall, valid (public) destination addresses are translated to static NAT
addresses.
In automatic Static NAT rules, statically translated public addresses are called
Valid Addresses and are used on the unprotected side of the VPN-1 gateway. The
actual addresses are private addresses that are used on the protected side of the
VPN-1 gateway.
Order of Automatic Rules
Automatic rules are placed in the Address Translation Rule Base in the following
order:
1. Static NAT rules before Hide NAT rules.
2. NAT on a node before NAT on a network or an address range.
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Check Point Solution for Network Address Translation
Port Translation
Port Translation allows multiple application servers in a hidden network to be
accessed using a single IP address, based on the requested service (or destination
port), which saves scarce public IP addresses. A typical implementation enables an
FTP server (accessible via port 21), an SMTP server (port 25) and an HTTP server
(port 80) to be accessed using a single IP public address.
To use Port Translation you need to create manual NAT rules. Port Translation rules
are supported on VPN-1 gateway versions NG FP3 and higher.
NAT and Anti-Spoofing
NAT is performed after anti-spoofing checks, which are performed only on the
source IP address of the packet. This means that spoofing protection is configured
on the interfaces of the VPN-1 gateway in the same way as NAT. Unlike in previous
versions of VPN-1, there are no special requirements for anti-spoofing configuration
and NAT.
Routing Issues
Static Routes on the VPN-1 Gateway
This section is intended for administrators who have upgraded the SmartCenter
server, where in the pre-upgrade:
•
Automatic NAT for the server was performed on the server side for pre-NG
versions, or
•
Manual NAT for the server was performed on the server side for pre-NG FP3
versions.
For a client-server connection that crosses the VPN-1 gateway, connections
originate at the client and the server sends reply packets back to the client.
In NG or higher versions of VPN-1, for both manual and automatic rules, NAT for
the server is performed by default on the client side of the VPN-1 gateway
(Figure 3-7), which ensures that the operating system routes the packets correctly.
In Figure 3-7, for the original packet, the VPN-1 gateway translates the destination
address to the valid address of the server and then routes the packet to its
destination.
Chapter 3
Network Address Translation (NAT) 111
Check Point Solution for Network Address Translation
For reply packets, no NAT is performed on the destination, and the operating
system correctly routes the packet back to the client.
Figure 3-7 NAT on the Client Side
The default setting for NG and higher versions ensures reliable anti-spoofing and
routing. It is recommended to leave the default setting unless you have upgraded
your SmartCenter server from a pre-NG version or have VPN-1 gateways whose
configuration requires other settings.
If NAT for the server destination is performed on the server side, the operating
system receives the packet for routing before NAT is performed. The operating
system therefore sees a valid address as the destination, and routes the packet
back to the Internet router rather than to the server. To resolve this, configure
Static Host Routes on the VPN-1 gateway so that it forwards packets to the correct
interface, for example, route add 192.168.0.3 10.1.1.2.
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Check Point Solution for Network Address Translation
Automatic and Proxy ARP
Giving a machine in the internal network an external IP address using NAT makes
that machine appear to the Internet to be on the external network, or the Internet
side of the firewall.
When NAT is configured automatically, the VPN-1 gateway machine replies on
behalf of translated network objects to ARP requests from the Internet router for
the address of the internal machine (Figure 3-8).
Figure 3-8 Automatic ARP Configuration
If you are using manual rules, you must configure proxy ARPs in order to associate
the translated IP address with the MAC address of the VPN-1 gateway interface
that is on the same network as the translated addresses.
Disabling NAT in a VPN Tunnel
When communicating within a VPN, it is normally not necessary to perform NAT.
You can disable NAT in a VPN tunnel with a single click in the VPN community
object. Disabling NAT in a VPN tunnel by defining a NAT rule slows down the
performance of the VPN.
Chapter 3
Network Address Translation (NAT) 113
Planning Considerations for NAT
Planning Considerations for NAT
In This Section
Hide Versus Static
page 114
Automatic Versus Manual Rules
page 114
Choosing the Hide Address in Hide NAT
page 115
Hide Versus Static
For protocols where the port number cannot be changed, Hide NAT cannot be used.
When the external server must distinguish between clients based on their IP
addresses, Hide NAT cannot be used because all clients share the same IP address
under Hide NAT.
To allow connections from the external network to the internal network, only Static
NAT can be used.
Automatic Versus Manual Rules
Automatic NAT rules are easy to configure and therefore are less prone to
configuration errors. Automatic ARP configuration is only effective for automatic
rules.
Manually defining NAT rules can be complicated, but it gives you complete control
over NAT. The following operations can only be performed using manual NAT rules:
114
•
Restricting rules to specified destination IP addresses and to specified source
IP addresses.
•
Translating both source and destination IP addresses in the same packet.
•
Performing Static NAT in only one direction.
•
Translating services (destination ports).
•
Restricting rules to specified services (ports).
•
Performing NAT on dynamic objects.
Planning Considerations for NAT
Choosing the Hide Address in Hide NAT
The Hide Address is the address behind which the network, address range or node
is hidden.
It is possible to hide behind either the interface of the Install on Gateway or a
specified IP address.
Choosing a fixed public IP address is a good option if you want to hide the address
of the VPN-1 gateway, however, it means you have to use an extra publicly routable
IP address.
Choosing to hide behind the address of the Install On Gateway is a good option for
administrative purposes, for example, if the external IP address of the firewall
changes, there is no need to change the NAT settings.
Chapter 3
Network Address Translation (NAT) 115
Configuring NAT
Configuring NAT
In This Section
General Steps for Configuring NAT
page 116
Basic Configuration (Network Node with Hide NAT)
page 117
Sample Configuration (Static and Hide NAT)
page 118
Sample Configuration (Using Manual Rules for Port Translation)
page 120
Configuring Automatic Hide NAT for Internal Networks
page 121
General Steps for Configuring NAT
To configure NAT:
1. Determine the IP addresses to be used for translation.
2. Define the network objects.
3. Define the Access rules in the Rule Base. When defining Manual NAT rules, you
must define network objects with translated addresses. If using Automatic NAT
rules, you must define only one network object per real object. For example, if
Static NAT is defined on an object called Alaska_Web, then the Rule Base only
needs to refer to Alaska_Web (Table 3-1) and there is no need to define a rule
for Alaska_Web (Valid Address).
Table 3-1
Rule Base Rule for an Object with Automatic NAT
Source
Destination
Action
Any
Alaska_Web
Accep
t
4. Define NAT rules (automatic and/or manual).
5. Install the security policy.
116
Configuring NAT
Basic Configuration (Network Node with Hide NAT)
Figure 3-9 shows the basic configuration for a network node with Hide NAT. The
aim is to hide the IP address of the Alaska_Web Web server (10.1.1.10) from
connections that originate on the Internet. Alaska_GW has three interfaces, one of
which faces the network where Alaska_Web resides.
Figure 3-9 Network Node with Hide NAT
1. Edit the node object for Alaska_Web, and in the NAT page, select Add Automatic
Address Translation rules (Figure 3-10).
Figure 3-10 Hide NAT Configuration
Chapter 3
Network Address Translation (NAT) 117
Configuring NAT
2. Select Translation Method Hide and the Hide behind the interface of the Install on
Gateway option.
3. Select Install on Gateway. In this example, the NAT gateway is Alaska_GW,
therefore, select either Alaska_GW or All.
Packets originating from Alaska_Web, with the Internet as their destination, have
their source address translated from 10.1.1.10 to 192.168.0.1. For example,
packets originating from the Web server have their source address changed from
172.16.10.3 to 192.168.0.1.
Sample Configuration (Static and Hide NAT)
In Figure 3-11, the objective is make the SMTP and the HTTP servers on the
internal network available to the Internet using public addresses and to provide
Internet access to all users on the internal network.
Figure 3-11 Sample Configuration (Static and Hide NAT)
The web and mail servers require static translation because incoming connections
are made to them from the Internet. Two routable addresses are available. In this
example, 192.168.0.5 is used for the Alaska.Web HTTP server and 192.168.0.6 is
used for the Alaska.Mail SMTP server.
The internal clients require hide translation because they will initiate connections.
No incoming connections are allowed to them from the Internet. They will hide
behind the external interface of the VPN-1 gateway.
To perform a sample configuration with Static and Hide NAT:
1. Define network objects for Alaska.Web (10.1.1.5), Alaska.Mail (10.1.1.6),
Alaska_LAN (10.1.1.0 with Net Mask 255.255.255.0) and the VPN-1 gateway
(Alaska.GW).
118
Configuring NAT
2. Edit the Alaska.Web object and in the NAT page, select Add Automatic Address
Translation Rules.
3. Select Static as the Translation Method and define the Translate to IP Address as
192.168.0.5.
4. For Alaska.Mail, select Static as the Translation Method and define the Translate
to IP Address as 192.168.0.6.
5. Edit the Alaska_LAN object and in the NAT page, select Hide as the Translation
Method and then select Hide behind the interface of the Install On Gateway. The
effective Hide address for the internal clients on Alaska_LAN is therefore
192.168.0.1. Figure 3-12 displays the resulting Address Translation Rule Base.
Figure 3-12 Automatic Address Translation Rule Base for Static and Hide NAT
Chapter 3
Network Address Translation (NAT) 119
Configuring NAT
Sample Configuration (Using Manual Rules for Port
Translation)
In Figure 3-13, the objective is to make both a Web server and a mail server in a
DMZ network available from the Internet using a single IP address. Hide NAT is
performed on all addresses in the DMZ.
Figure 3-13 Sample Configuration (Port Translation using Manual NAT)
To perform a sample configuration using manual rules for port translation:
1. Define network objects for the network Alaska.DMZ.LAN (172.16.0.0 with Net
Mask 255.255.0.0), the Web server Alaska_DMZ_Web (172.16.1.7), the Mail
server Alaska_DMZ_Mail (172.16.1.5) and the VPN-1 gateway (Alaska.GW).
2. In the NAT tab on the Alaska.DMZ.LAN network object, select Add Automatic
Address Translation Rules.
3. Select Hide as the Translation Method and then Hide behind the interface of the
Install on Gateway. This step adds two automatic rules to the Address
Translation Rule Base (Rules 1 and 2 in Figure 3-14).
4. In the Address Translation Rule Base, define a Manual NAT rule that translates
requests for the HTTP service to the Web server (Rule 3 in Figure 3-14) and a
Manual NAT rule to translate SMTP requests to the SMTP server (Rule 4 in
Figure 3-14).
120
Configuring NAT
Figure 3-14 Address Translation Rule Base for Port Translation
Configuring Automatic Hide NAT for Internal
Networks
To configure automatic Hide NAT for internal networks:
1. Access the NAT page of the Check Point gateway object.
2. In the Automatic Hide for Internal Networks section, either select or clear the
Hide all connections from internal interfaces to external interfaces behind the
gateway option.
For additional information on configuring automatic Hide NAT for internal networks,
refer to See “Automatic Hide NAT for Internal Networks” on page 106.”
Chapter 3
Network Address Translation (NAT) 121
Advanced NAT Configuration
Advanced NAT Configuration
In This Section
Allowing Connections Between Translated Objects on Different Gateway
Interfaces
page 122
Enabling Communication for Internal Networks with Overlapping IP
Addresses
page 123
SmartCenter Behind NAT
page 127
IP Pool NAT
page 131
Allowing Connections Between Translated Objects
on Different Gateway Interfaces
The following sections describe how to allow connections in both directions
between statically translated objects (nodes, networks or address ranges) on
different VPN-1 gateway interfaces.
If NAT is defined through the network object (as opposed to using Manual NAT
Rules), then you must ensure that bidirectional NAT is enabled.
122
Advanced NAT Configuration
Enabling Communication for Internal Networks with
Overlapping IP Addresses
Overview
If two internal networks have overlapping (or partially overlapping) IP addresses,
VPN-1 enables:
•
Communication between the overlapping internal networks.
•
Communication between the overlapping internal networks and the outside
world.
•
Enforcement of a different security policy for each of the overlapping internal
networks.
Network Configuration
Figure 3-15 is a sample network configuration.
Figure 3-15 Sample Network Configuration:Class C Network
In Figure 3-15, both Network A and Network B share the same address space
(192.168.1.0/24), therefore standard NAT cannot be used to enable
communication between the two networks. Instead, overlapping NAT must be
performed on a per interface basis.
Users in Network A who want to communicate with users in Network B must use
the 192.168.30.0/24 network as a destination. Users in Network B who want to
communicate with users in Network A must use the 192.168.20.0/24 network as a
destination.
Chapter 3
Network Address Translation (NAT) 123
Advanced NAT Configuration
The VPN-1 gateway translates the IP addresses in the following way for each
individual interface:
Interface A
•
Inbound source IP addresses are translated to the virtual network
192.168.20.0/24.
•
Outbound destination IP addresses are translated to the network
192.168.1.0/24.
Interface B
•
Inbound source IP addresses are translated to the network 192.168.30.0/24.
•
Outbound destination IP addresses are translated to the network
192.168.1.0/24.
Interface C
Overlapping NAT is not configured for this interface. Instead, use NAT Hide in the
normal way (not on a per-interface basis) to hide source addresses behind the
interface’s IP address (192.168.4.1).
Communication Examples
This section describes how to enable communication between internal networks,
and between an internal network and the Internet
Communication Between Internal Networks
If user A, at IP address 192.168.1.10 in Network A, wants to connect to user B, at
IP address 192.168.1.10 (the same IP address) in Network B, user A opens a
connection to the IP address 192.168.30.10 (Table 3-2).
Table 3-2
Step
Source IP address
Destination IP address
Interface A — before NAT
192.168.1.10
192.168.30.10
Interface A — after NAT
192.168.20.10
192.168.30.10
VPN-1 gateway enforces the security policy for packets from network 192.168.20.0/24
to network 192.168.30.0/24.
Interface B — before NAT
192.168.20.10
192.168.30.10
Interface B — after NAT
192.168.20.10
192.168.1.10
124
Advanced NAT Configuration
Communication Between an Internal Network and the Internet
If user A, at IP address 192.168.1.10 in network A, connects to IP address
10.10.10.10 on the Internet (Table 3-3).
Table 3-3
Step
Source IP address
Destination IP address
Interface A — before NAT
192.168.1.10
10.10.10.10
Interface A — after NAT
192.168.20.10
10.10.10.10
VPN-1 gateway enforces the security policy for packets from network 192.168.20.0/24
to the Internet.
Interface C — before NAT
192.168.20.10
10.10.10.10
Interface C — after NAT Hide
192.168.4.1
10.10.10.10
Routing Considerations
In order to allow routing from Network A to Network B, routing must be configured
on the firewall machine. The following are routing command examples for Windows
and Linux operating systems (for other operating systems, use the equivalent
commands):
On Windows
•
route add 192.168.30.0 mask 255.255.255.0 192.168.3.2
•
route add 192.168.20.0 mask 255.255.255.0 192.168.2.2
On Linux
•
route add -net 192.168.30.0/24 gw 192.168.3.2
•
route add -net 192.168.20.0/24 gw 192.168.2.2
Chapter 3
Network Address Translation (NAT) 125
Advanced NAT Configuration
VPN-1 Object Database Configuration
To activate the overlapping NAT feature, use the dbedit database editor GUI (or
command line utility).
In the sample network configuration (Figure 3-15), the per interface values for
interface A and interface B are set in the following way:
Table 3-4
126
Parameter
Value
enable_overlapping_nat
true
overlap_nat_dst_ipaddr
The overlapping IP addresses (before NAT). In
the sample network configuration, 192.168.1.0
for both interfaces.
overlap_nat_src_ipaddr
The IP addresses after NAT. In the sample
network configuration, 192.168.20.0 for
interface A, and 192.168.30.0 for interface B.
overlap_nat_netmask
The net mask of the overlapping IP addresses.
In the sample network configuration,
255.255.255.0.
Advanced NAT Configuration
SmartCenter Behind NAT
The SmartCenter server sometimes uses a private IP address (as listed in RFC
1918) or some other non-routable IP address, because of the lack of public IP
addresses.
NAT (Static or Hide) for the SmartCenter server IP address can be configured in
one click, while still allowing connectivity with managed gateways. All gateways can
be controlled from the SmartCenter server, and logs can be sent to the SmartCenter
server. NAT can also be configured for a Management High Availability server and a
Log server.
Note - SmartCenter behind NAT is not supported for deployments where the SmartCenter
server also acts as a gateway and must be addressed from outside the NATed domain, for
example, when it receives SAM commands.
Figure 3-16 is a typical SmartCenter Behind NAT scenario. The SmartCenter server
is in a network on which Network Address Translation is performed (the “NATed
network”). The SmartCenter server can control Check Point gateways inside the
NATed network, on the border between the NATed network and the outside world
and outside the NATed network.
Figure 3-16 SmartCenter Behind NAT Scenario
In ordinary Hide NAT configurations, connections cannot be established from the
external side the VPN-1 NAT gateway. However, when using Hide NAT on the
SmartCenter server, gateways can send logs to the SmartCenter server.
When using the SmartCenter behind NAT feature, the gateway (the remote module)
automatically selects the SmartCenter address to be addressed and simultaneously
applies NAT considerations.
To enable NAT for the SmartCenter server:
•
From the NAT page of the SmartCenter server object, define NAT and select
Apply for VPN-1 control connections.
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Network Address Translation (NAT) 127
Advanced NAT Configuration
Non-corresponding Gateway Addresses
In certain situations the gateway contacts the SmartCenter with an address that
does not correspond to the remote gateway’s deployment, for example:
•
When there are gateways from a version prior to NG with Application
Intelligence. In this case, refer to SecureKnowledge solution SK15558 at
https://secureknowledge.checkpoint.com/ for further instructions.
•
When the gateway’s automatic selection does not conform with the routing of
the gateway’s deployment. In this case, define the masters and loggers
manually in order to allow the remote gateway to contact the SmartCenter
server using the required address. When an inbound connection from a
managed gateway enters the VPN-1 gateway, port translation is used to
translate the hide address to the real IP address of the SmartCenter server.
To define masters and loggers:
•
Select Use local definitions for Log Servers and Use local definitions for Masters
and specify the correct IP addresses on the gateway.
This solution encompasses two scenarios:
•
The remote gateway addresses the NATed IP when you want it to address
the real IP.
•
The remote gateway addresses the real IP when you want it to address the
NATed IP. In this case, specify the SIC name of the SmartCenter server in
the masters file.
Note that:
128
•
Only one object can be defined with these settings, unless the second
object is defined as a Secondary SmartCenter server or as a Log server.
•
Ensure that you properly define the Topology settings on all gateways. In
Figure 3-16, on California_GW, define the Primary_SmartCenter on its
internal interface.
•
All managed gateways and the SmartCenter server must be of version NG
with Application Intelligence or higher.
•
In previous versions, various work-arounds were required. All previous
work-arounds still work with no changes in their behavior.
Advanced NAT Configuration
Configuring the SmartCenter Server Object
To configure the SmartCenter server object:
1. From the NAT page on the Primary_SmartCenter object, select either Static NAT
or Hide NAT. If using Hide NAT, select Hide behind IP Address, for example,
192.168.55.1. Do not select Hide behind Gateway (address 0.0.0.0).
2. Select Install on Gateway to protect the NATed objects or network. Do not select
All. For example, in Figure 3-16, Install on Gateway: California_GW.
3. Select Apply for VPN-1 control connections.
Configuring the Gateway Object
Using the example provided in Figure 3-16, ensure that the California_GW knows
that the Primary_SmartCenter is behind it.
To configure the gateway object:
1. From the California_GW Topology page, define Interface Eth3.
2. In the General tab of the Interface Properties window, define the IP Address
10.0.0.0 and the Netmask 255.255.0.0.
In the Topology tab of the Interface Properties window, select Network defined by the
interface IP and Net Mask.
Configuring Gateway Objects of Pre-NG with Application
Intelligence Versions
For managed gateways that are not version NG with Application Intelligence or
higher, you must define a dummy object. Using the example provided in
Figure 3-16, if Florida_GW and California_GW have a version lower than NG with
Application Intelligence, the dummy objects ensure that Florida_GW knows that its
SmartCenter server has the address 192.168.255.1 and California_GW knows that
its SmartCenter server has the address 10.0.0.1.
To configure pre-NG version with Application Intelligence gateway objects:
1. Define a dummy object with the translated address of the Primary_SmartCenter.
1. Name it, for example, Dummy-SmartCenter.
2. in the Check Point Products section of the General Properties page, select
Secondary Management Station and Log Server.
3. Define a dummy object for the California_GW object by doing the following:
Chapter 3
Network Address Translation (NAT) 129
Advanced NAT Configuration
a. Name it.
b. Assign the IP Address 192.168.255.1.
c. Assign the address of the Primary SmartCenter NAT definition.
d. In the Check Point Products section of the General Properties page, select
Secondary Management Station and Log Server.
e. From the Logs and Masters page:
i.
Define the dummy object as a Master.
ii. Define the dummy object as a Log server (if the Log server is on a
separate machine, define two virtual objects).
130
Advanced NAT Configuration
IP Pool NAT
An IP Pool is a range of IP addresses (an address range, a network or a group of
one of these objects) that is routable to the gateway. IP Pool NAT ensures proper
routing for encrypted connections for the following two connection scenarios:
•
SecuRemote/SecureClient to MEP (Multiple Entry Point) gateways
•
Gateway to MEP gateways
When a connection is opened from a SecuRemote/SecureClient or a client behind a
gateway to a server behind the MEP Gateways, the packets are routed through one
of the MEP gateways. Return packets in the connection must be routed back
through the same gateway in order to maintain the connection. To ensure that this
occurs, each of the MEP gateways maintains a pool of IP addresses that are
routable to the gateway. When a connection is opened to a server, the gateway
substitutes an IP address from the IP pool for the source IP address. Reply packets
from the server return to the gateway, which restores the original source IP address
and forwards the packets to the source.
The pool of IP addresses is configured in the IP Pool page of the gateway object.
For additional information on how IP Pool NAT is used in MEP scenarios, refer to
Chapter 11 “Multiple Entry Point VPNs” in the Virtual Private Networks
Administration Guide.
IP Pool Per Interface
You can define a separate IP address pool on one or more of the gateway interfaces
instead of defining a single pool of IPs for the gateway.
Defining an IP pool per interface solves routing issues that occur when the gateway
has more than two interfaces. Sometimes it is necessary that reply packets return
to the gateway through the same gateway interface. Figure 3-17 shows one of the
MEP Gateways in a SecuRemote/SecureClient to MEP (Multiple Entry Point)
gateway deployment.
Chapter 3
Network Address Translation (NAT) 131
Advanced NAT Configuration
Figure 3-17 IP Pool Per Interface
If a remote client opens a connection to the internal network, reply packets from
hosts inside the internal networks are routed to the correct gateway interface
through the use of static IP pool NAT addresses.
The remote VPN client’s IP address is NATed to an address in the IP pool on one of
the gateway interfaces. The addresses in the IP pool can be routed only through
that gateway interface so that all reply packets from the target host are returned
only to that interface. Therefore, it is important that the IP NAT pools of the
interfaces do not overlap.
When the packet returns to the gateway interface, the gateway restores the remote
peer’s source IP address.
The routing tables on the routers that lie behind the gateway must be edited so that
addresses from a gateway IP pool are returned to the correct gateway interface.
Switching between IP Pool NAT per gateway and IP Pool NAT per interface and
then installing the security policy deletes all IP Pool allocation and all NATed
connections.
132
Advanced NAT Configuration
NAT Priorities
IP Pool NAT can be used both for encrypted (VPN) and clear (decrypted by the
gateway) connections.
Note - To enable IP Pool NAT for clear connections through the gateway, configure
INSPECT changes in the user.def file. For additional information, contact Check Point
Technical Support.
For non-encrypted connections, IP Pool NAT has the following advantages over Hide
NAT:
•
New back connections (for example, X11) can be opened to the NATed host.
•
User-to-IP server mapping of protocols that allow one connection per IP can
work with a number of hosts instead of only one host.
•
IPSec, GRE and IGMP protocols can be NATed using IP Pool NAT (and Static
NAT). Hide NAT works only with TCP, UDP and ICMP protocols.
Because of these advantages, you can specify that IP Pool NAT has priority over
Hide NAT, if both match the same connection. Hide NAT is only applied if the IP
pool is used up.
The order of NAT priorities are:
1. Static NAT
2. IP Pool NAT
3. Hide NAT
Since Static NAT has all of the advantages of IP Pool NAT and more, it has a higher
priority than the other NAT methods.
For gateways of versions lower than NGX (R60) and for upgraded gateways (by
default), the order of NAT priorities are:
1. Static NAT
2. Hide NAT
3. IP Pool NAT
Chapter 3
Network Address Translation (NAT) 133
Advanced NAT Configuration
Reusing IP Pool Addresses For Different Destinations
For pre-NGX (R60) gateways that are using IP Pool NAT, if an IP pool contains N
addresses, up to N different clients can be NATed.
From gateway version NGX (R60), IP Pool addresses can be reused for different
destinations, which makes more efficient use of the addresses in the pool. If a pool
contains N addresses, then any number of clients can be assigned an IP from the
pool as long as there are no more then N clients per server.
Using IP Pool allocation per destination, two different clients can receive the same
IP from the pool as long as they communicate with different servers (connections 1
and 2 in Figure 3-18). When reusing addresses from the IP Pool, back connections
are supported from the original server only. This means that connections back to
the client can be opened only from the specific server to which the connection was
opened (connection 3 in Figure 3-18).
Figure 3-18 Reusing IP Pool NAT Addresses For Different Destinations
The default Do not reuse IP Pool behavior means that each IP address in the IP Pool
is used once (connections 1 and 2 in Figure 3-19). In this mode, if an IP pool
contains 20 addresses, up to 20 different clients can be NATed and back
connections can be opened from any source to the client (connection 3 in
Figure 3-19).
134
Advanced NAT Configuration
Figure 3-19 Do Not Reuse IP Pool NAT Addresses
Switching between Reuse and Do not reuse modes and then installing the security
policy, deletes all IP Pool allocations and all NATed connections.
Configuring IP Pool NAT
To configure IP Pool NAT:
1. In the Global Properties > NAT page, select Enable IP Pool NAT and the required
tracking options.
2. In the gateway General Properties page, ensure the gateway version is specified
correctly. IP Pool NAT can be defined per gateway or, for gateways of version
NGX (R60) or higher, per gateway interface.
3. For each gateway or gateway interface, create a network object that represents
its IP pool NAT addresses. The IP pool can be a network, group, or address
range. For example, for an address range, do the following:
•
In the network objects tree, right-click Network Objects branch and select
New > Address Range... The Address Range Properties window opens.
•
In the General tab, enter the first and last IP of the address range.
•
Click OK. The new address range appears in the Address Ranges branch of
the network objects tree.
4. Select the gateway object, access the Gateway Properties window and select NAT
> IP Pool NAT.
5. In the IP Pool NAT page, select one of the following:
•
Allocate IP Addresses from and then select the address range you created to
configure IP Pool NAT for the whole gateway, or
Chapter 3
Network Address Translation (NAT) 135
Advanced NAT Configuration
•
Define IP Pool addresses on gateway interfaces to configure IP Pool NAT per
interface.
6. If required, select one or more of the following options:
•
Use IP Pool NAT for VPN client connections
•
Use IP Pool NAT for gateway to gateway connections
•
Prefer IP Pool NAT over Hide NAT to specify that IP Pool NAT has priority over
Hide NAT, if both match the same connection. Hide NAT is only applied if
the IP pool is used up.
7. Click Advanced.
•
Return unused addresses to IP Pool after: Addresses in the pool are reserved
for t60 minutes (default), even if the user logs off. If the user disconnects
from their ISP and then redials and reconnects, there will be two Pool NAT
addresses in use for the user until the first address from the IP Pool times
out. If users regularly lose their ISP connections, you may want to decrease
the time-out to prevent the IP Pool from being depleted.
•
Reuse IP addresses from the pool for different destinations: This is a good
option unless you need to allow back connections to be opened to clients
from any source, rather than just from the specific server to which the
client originally opened the connection.
8. Click OK.
9. Edit the routing table of each internal router so that packets with an a IP
address assigned from the NAT pool are routed to the appropriate gateway or, if
using IP Pools per interface, the appropriate gateway interface.
IP Pool NAT for Clusters
IP Pools for gateway clusters are configured in two places in SmartDashboard:
136
•
In the gateway Cluster object NAT > IP Pool NAT page, select the connection
scenario.
•
In the Cluster member object IP Pool NAT page, define the IP Pool on the
cluster member. A separate IP pool must be configured for each cluster
member. It is not possible to define a separate IP Pool for each cluster member
interface.
Chapter
ISP Redundancy
4
In This Chapter
The Need for ISP Link Redundancy
page 138
Solution for ISP Link Redundancy
page 139
Considerations for ISP Link Redundancy
page 149
Configuring ISP Link Redundancy
page 150
137
The Need for ISP Link Redundancy
The Need for ISP Link Redundancy
As Internet access becomes increasingly critical to business success, the costs
associated with the loss of connectivity become greater. To protect against network
downtime, it makes sense to deploy redundant systems for mission critical Internet
applications. Connecting to the Internet through more than one Internet Service
Provider (ISP) provides that additional redundancy.
A number of solutions are available on the market that enable connections to
multiple ISPs, however, these solutions often require expensive and specialized
hardware and are difficult to set up and maintain. A simple solution is required
that makes use of the existing boundary between the Internet and the organization,
which is the firewalled gateway.
138
Solution for ISP Link Redundancy
Solution for ISP Link Redundancy
In This Section
ISP Redundancy Overview
page 139
ISP Redundancy Operational Modes
page 140
Monitoring the ISP Links
page 141
How ISP Redundancy Works
page 141
ISP Redundancy Script
page 143
Manually Changing the Link Status (fw isp_link)
page 143
ISP Redundancy Deployments
page 144
ISP Redundancy and VPNs
page 147
ISP Redundancy Overview
ISP Redundancy assures reliable Internet connectivity by allowing a single or
clustered VPN-1 gateway to connect to the Internet through redundant Internet
Service Provider (ISP) links. This feature is part of the standard VPN-1 installation
and does not require costly new networking hardware or specialized knowledge to
operate.
ISP Redundancy is supported on VPN-1 NG with Application Intelligence (R55)
gateways or higher on the following platforms:
•
Red Hat Linux 7.2 or higher
•
SecurePlatform
•
IPSO
ISP Redundancy monitors the ISP links and directs connections to the appropriate
link, depending on the operating mode. Two modes are available: Load Sharing and
Primary/Backup.
Figure 4-1 is a typical deployment with a single ISP link and redundant deployment
with duplicate ISP links.
Chapter 4
ISP Redundancy 139
Solution for ISP Link Redundancy
Figure 4-1
ISP Link Redundancy
ISP Redundancy Operational Modes
The following ISP Redundancy modes control the behavior of outgoing connections
from clients in the internal networks to the Internet:
•
Primary/Backup: Connects to an ISP through the primary link and switches to a
backup ISP when the primary ISP link fails. When the primary link is restored,
new outgoing connections are assigned to it, while existing connections are
maintained over the backup link until they are complete.
•
Load Sharing: Connects to both ISPs while distributing the load of outgoing
connections between the ISPs. New connections are randomly assigned to a
link. If a link fails, all new outgoing connections are directed to the active link.
Incoming connections (from the Internet to application servers in the DMZ or
internal networks) also benefit from the high availability of the two ISP links
because VPN-1 returns packets using the same ISP Link through which the
connection was initiated.
Furthermore, in Load Sharing mode, incoming connections can reach the
application servers through either ISP link because VPN-1 can answer DNS
requests for the IP address of internal servers with addresses from both ISPs by
alternating their order.
140
Solution for ISP Link Redundancy
Monitoring the ISP Links
ISP Redundancy monitors the status of the ISP links and directs outgoing
connections to the appropriate link.
To monitor the status of the link, VPN-1 checks whether or not the interface is
running and if the cable is plugged in. The next hop router is monitored
automatically.
Another way of monitoring the status of the ISP link is for the administrator to
configure a list of hosts that must answer ICMP echo requests (pings) in order for
the ISP link to be considered active. If one of the hosts fails to return ICMP
replies, the link is considered to be down. You may opt to include hosts such as an
ISP Web server or some other host on the Internet.
The status of the ISP links is reported by SmartView Monitor in the Firewall section.
How ISP Redundancy Works
Both outgoing connections, from behind the VPN-1 gateway towards the Internet,
and incoming connections, from the Internet, benefit from the existence of
duplicate links.
Outgoing Connections
In Load Sharing mode, outgoing traffic that exits the VPN-1 gateway on its way to
the Internet is distributed between the ISP Links. In Primary/Backup mode,
outgoing traffic uses an active primary link.
Hide NAT is used to change the source address of outgoing packets to the address
of the interface through which the packet leaves the VPN-1 gateway. This allows
return packets to be automatically routed through the same ISP link because their
destination address is the address of the correct link. Hide NAT is configured by
the administrator.
Incoming Connections
For external users to make incoming connections, the administrator must give each
application server two routable IP addresses, one for each ISP. The administrator
must also configure Static NAT to translate the routable addresses to the real server
address.
If the servers handle different services (for example, HTTP and FTP), you can use
NAT to employ only two routable IP addresses for all the publicly available servers.
Chapter 4
ISP Redundancy 141
Solution for ISP Link Redundancy
External clients use one of the two addresses. In order to connect, the clients must
be able to resolve the DNS name of the server to the correct IP address.
Note - In the following example, the subnets
represent public routable addresses.
172.16.0.0/24 and 192.168.0.0/24
In Figure 4-2, the Web server www.example.com is assigned an IP address from
each ISP: 192.168.1.2 from ISP A, and 172.16.2.2 from ISP B. If the ISP link A
is down, 192.168.1.2 becomes unavailable and the clients must be able to resolve
www.example.com to 172.16.2.2.
Figure 4-2 IP Address Resolution for Incoming Connections
The following is a workflow, based on Figure 4-2, of how an incoming connection is
established:
1. When a user in the Internet contacts www.example.com, the client machine
sends a DNS query for the IP address. The DNS query reaches the VPN-1
gateway. VPN-1 has a built-in mini-DNS server that can be configured to
intercept DNS queries (of type A) for servers in its domain.
2. A DNS query arriving at an interface belonging to one of the ISP links is
intercepted by VPN-1.
3. If VPN-1 recognizes the name of the host, it sends one of the following replies:
142
•
In Primary/Backup mode, VPN-1 replies only with the addresses associated
with the primary link, as long as the primary link is active.
•
In Load Sharing mode, VPN-1 replies with two addresses, alternating their
order.
Solution for ISP Link Redundancy
4. If VPN-1 is unable to handle DNS requests (for example, it may not recognize
the host name,), it passes the DNS query to its original destination or the DNS
server of the domain example.com.
5. When the external client receives the reply to its DNS query, it opens a
connection. Once the packets reach the gateway, VPN-1 uses Static NAT to
translate the destination address 192.168.1.2 or 172.16.2.2 to the real server
address 10.0.0.2.
6. VPN-1 routes reply packets from the server to the client through the same ISP
link that was used to initiate the connection.
ISP Redundancy Script
Whenever VPN-1 starts or an ISP link state changes, a script is run. Depending on
whether the ISP link is up or down, this script automatically changes the default
route of the VPN-1 gateway.
If one of the ISP links is a dialup interface, you can manually edit the ISP
Redundancy script to make the VPN-1 change the state of the dialup interface
when the ISP links state changes or when the VPN-1 starts.
The script can also be configured to perform other actions, for example, to issue a
SAM command to block certain traffic when the primary link is down in order to
decrease the traffic load on the link.
The name and location of the ISP Redundancy script is $FWDIR/bin/cpisp_update.
Manually Changing the Link Status (fw isp_link)
The fw isp_link command is used to configure the ISP link on VPN-1 to Down or
Up and is helpful:
•
When testing your configuration.
•
When you know the ISP link is down, but VPN-1 thinks it is up. In this case,
use the command to bring the link back up when the link actually becomes
available.
This command can be executed locally on the gateway or remotely from the
SmartCenter server. When executed from the SmartCenter server, you must provide
the fw isp_link [target] link-name up|down target argument, where <target>
is the name of the gateway and <link-name> is the name of the ISP link, as
defined in the ISP Redundancy page of the gateway or gateway Cluster object.
Chapter 4
ISP Redundancy 143
Solution for ISP Link Redundancy
ISP Redundancy Deployments
A number of deployments are supported. For additional information on each
deployment type, refer to “Considerations for ISP Link Redundancy” on page 149.
Two External Interfaces
The easiest way to connect to two ISPs is to connect each VPN-1 gateway interface
to a different ISP through a LAN (Figure 4-3). The next hop routers are either at
the boundary of the organization or at the ISP.
Figure 4-3 Two ISPs Connected to Different External VPN-1 Gateway Interfaces
144
Solution for ISP Link Redundancy
One External Interface
If only one external interface is available on the VPN-1 gateway, you can configure
two subnets on the same external interface. Both ISP links are then connected to
the same VPN-1 interface but to different next hop routers, usually through a
switch (Figure 4-4).
Figure 4-4 Two ISPs Connected to the Same VPN-1 Gateway External Interface
One Permanent and One Dialup (Backup) Interface
To connect to one of the ISPs through a dialup network (a modem) and to the other
ISP through a LAN, connect each VPN-1 gateway external interface to a different
ISP link (Figure 4-5). This deployment is useful if you have a dialup connection to
your backup ISP.
Figure 4-5 One ISP Link a LAN - One ISP Link a Dialup Network
Chapter 4
ISP Redundancy 145
Solution for ISP Link Redundancy
Gateway Cluster Connection
If you have a ClusterXL gateway cluster, connect each cluster member to both ISPs
through a LAN using two interfaces (Figure 4-6).
Configure ClusterXL in the usual way, however, ensure that the member interfaces
are on the same subnet as the cluster external interfaces (for additional
information, refer to the ClusterXL Administration Guide).
Figure 4-6 Both ISP Links are LANs Connected to a Gateway Cluster
146
Solution for ISP Link Redundancy
ISP Redundancy and VPNs
When ISP Redundancy is configured on the VPN-1 gateway, VPN encrypted
connections can survive a failure of one of the ISP links on the gateway. ISP
Redundancy works with both gateway to gateway VPNs and
SecuRemote/SecureClient to Remote Access VPNs.
The settings configured in the ISP Redundancy window, by default, are applied to
the Link Selection page and overwrite any pre-existing configuration. If
Primary/Backup mode is configured, it is transferred to the Link Selection
configuration.
To configure ISP Redundancy on the VPN-1 gateway:
1. Select VPN > Topology > ISP Redundancy. The ISP Redundancy window opens.
2. Configure the appropriate settings in the ISP Redundancy window. When ISP
Redundancy is configured, the default setting in the Link Selection page is Use
ongoing probing, however, Link Selection only probes the ISPs configured in the
ISP Redundancy window. This feature enables connection failover of the VPN
tunnel if connectivity to one of the gateway interfaces fails.
A different configuration for Link Selection is required when there are two gateways
with two ISPs (Figure 4-7).
Figure 4-7 Two Gateways with Two ISPs
In this case:
Chapter 4
ISP Redundancy 147
Solution for ISP Link Redundancy
•
Gateways A, B, and C have two ISPs.
•
ISP Redundancy is configured on gateway A.
•
Gateway A should use ISP 1 to connect to gateway B and ISP 2 to connect to
gateway C. If one of the ISPs becomes unavailable, the other ISP should be
used.
For additional configuration information, refer to the “Link Selection” chapter of
the VPN Administration Guide.
ISP Redundancy and Third-Party VPNs
The ability of a third-party VPN device to detect an ISP link failure depends on the
third-party device implementation. The failure of an ISP link could lead to a VPN
failure for the following reasons:
1. The third-party device may not recognize incoming encrypted traffic from the
secondary link as coming from the gateway.
2. The third-party device may be unable to detect an ISP link failure and therefore
may continue encrypting traffic to the failed link.
148
Considerations for ISP Link Redundancy
Considerations for ISP Link Redundancy
Choosing the Deployment
The choice of deployment that best suits your organization’s needs is normally
evident. The following are some recommendations:
•
The simplest configuration is to use a different interface for each ISP link, as
shown in Figure 4-3.
•
If only one external interface is available on the VPN-1 gateway, you can
connect both ISPs to the same interface by defining two subnets, one for each
ISP on the same interface, as shown in Figure 4-4 .
•
If one of the ISP links is a dialup network (modem connection) that is used for
backup, use the deployment shown in Figure 4-5 and select the
Primary/Backup mode of operation.
•
If the ISP links are connected to a VPN-1 gateway cluster, use the deployment
shown in Figure 4-6.
Choosing the Redundancy Mode
If both ISPs are basically the same, use Load Sharing mode to ensure that you are
making the best use of both ISPs.
You may prefer to use one of your two ISPs that is more cost-effective in terms of
price and reliability. In that case, use Primary/Backup mode and set the more
cost-effective ISP as the Primary ISP link.
Chapter 4
ISP Redundancy 149
Configuring ISP Link Redundancy
Configuring ISP Link Redundancy
In This Section
Introduction to ISP Link Redundancy Configuration
page 150
Registering the Domain and Obtaining IP Addresses
page 150
DNS Server Configuration for Incoming Connections
page 151
Dialup Link Setup for Incoming Connections
page 152
SmartDashboard Configuration
page 152
Configuring the Default Route for the ISP Redundancy Gateway
page 154
Introduction to ISP Link Redundancy Configuration
The following ISP Redundancy configuration allows outgoing connections from
behind the VPN-1 gateway to the Internet and incoming connections from the
Internet to the networks behind the VPN-1 gateway.
Note - For advanced configuration options, refer to SecureKnowledge solution sk23630 at
https://secureknowledge.checkpoint.com/ (your username and password are required).
Note -
In the following configuration examples, the subnets 192.168.1.0/24 and 172.16.2.0/24
represent public routable addresses.
Registering the Domain and Obtaining IP Addresses
The VPN-1 gateway, or a DNS server behind it, must respond to DNS queries and
resolve IP addresses that belong to publicly accessible servers in the DMZ (or
another internal network). It is not necessary to have an actual DNS server because
the VPN-1 gateway can be configured to intercept the DNS queries.
To register the domain and obtain IP addresses:
1. Obtain one routable IP address from each ISP for the DNS server or for the
VPN-1 gateway that intercepts DNS queries. If routable IP addresses are not
available, make the DNS server accessible from the Internet using manual NAT
(step 15).
2. Register your domain (for example, example.com) with both ISPs.
3. Inform both ISPs of the two addresses of the DNS server that respond to DNS
queries for the example.com domain.
150
Configuring ISP Link Redundancy
4. To allow incoming connections, obtain one routable IP address from each ISP
for each application server that is accessed from the Internet. For example, in
Figure 4-2 on page 142, obtain two IP addresses for the Web server in
DMZ-net. To avoid using routable IP addresses for the publicly available
servers, refer to step 15.
DNS Server Configuration for Incoming Connections
The following section describes a DNS server configuration for incoming
connections where the VPN-1 is configured to intercept DNS queries to a Web
server (for example, www.example.com in Figure 4-2 on page 142) that arrive at
the VPN-1 external interfaces and to respond to them with ISP addresses
192.168.1.2 and 172.16.2.2.
To configure the DNS server for incoming connections:
1. In the DNS Proxy tab of the ISP Redundancy window, select Enable DNS proxy.
2. VPN-1 responds to DNS queries with either one or two IP addresses, depending
on the status of the ISP link and the redundancy mode. To configure this
behavior, map each server name to an IP address pair by clicking Add… in the
DNS Proxy tab.
3. Type a Host name (for example, www.example.com).
4. Add an IP address for ISP-1 (for example, 192.168.1.2 in Figure 4-2 on
page 142) and an IP address for ISP-2 (for example, 172.16.2.2).
It is important to ensure that DNS servers in the Internet do not store
out-of-date address information. Each DNS reply has a Time To Live (TTL) field
which indicates to the recipients of the reply how long the information in the
reply may be cached. By default, VPN-1 replies with a TTL of 15 seconds. This
can be changed in the DNS TTL field.
Chapter 4
ISP Redundancy 151
Configuring ISP Link Redundancy
Dialup Link Setup for Incoming Connections
To configure a dialup link for incoming connections:
1. If one of the ISP links is a dialup network, edit the ISP Redundancy Script
located in $FWDIR/bin/cpisp_update.
2. In the script, use the Linux or SecurePlatform operating system command to
bring up or to take down the dialup interface.
3. You can connect SecurePlatform to ISPs that provide xDSL services using
PPPoE or PPTP xDSL modems. If using one of these connections, in the PPPoE
or PPTP configuration of SecurePlatform, clear the Use Peer Gateway option.
SmartDashboard Configuration
To configure SmartDashboard:
1. Define a Security Rule Base rule that accepts DNS traffic through the VPN-1
gateway using the domain_udp service.
2. In the Check Point Gateway window of the Topology page, define the VPN-1
interfaces leading to the ISPs.
3. Select Topology > ISP Redundancy and then the Support ISP Redundancy option.
4. Perform either Automatic ISP Link Configuration (follow step 5 to step 8) or
Manual ISP Link Configuration (follow step 9 to step 13). Automatic
configuration only works if there are exactly two external interfaces defined in
the Topology page (it does not work for gateway cluster objects).
Automatic ISP Link Configuration
5. Click Automatic ISP Links configuration to configure the ISP links based on
information taken from the routing table of the gateway and the Topology page
of the gateway object.
6. To work in Primary/Backup mode, do the following:
a. In the Redundancy Mode section, select Primary/Backup.
b. Select the link and then Edit to define the link you want to be primary.
c. In the General tab of the ISP Link Properties window, select Primary ISP.
7. Examine the automatically configured ISP Links configuration for correctness.
8. Continue to step 14.
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Configuring ISP Link Redundancy
Manual ISP Link Configuration
9. In the Redundancy Mode section, select Load Sharing or Primary/Backup.
10. Click Add to define each of the ISP links.
11. In the General tab of the ISP Link Properties window, configure the following:
a. Name the ISP link and select the Interface leading to the ISP.
b. Specify the Next Hop IP Address by clicking Get from routing table. If the ISP
link is a dialup connection, leave the Next Hop IP Address field blank.
In Figure 4-3 on page 144, the next hop router on the way to ISP A has the
IP address 192.168.1.1 and the next hop router on the way to ISP B has
the IP address 172.16.2.1.
c. In Primary/Backup mode, define whether the ISP link is Primary.
12. Define a list of hosts to be monitored to verify that the link is operational. To
specify the hosts, select the Advanced tab of the ISP Link Properties window and
then Add to add the hosts to the list of Selected hosts.
13. Define Tracking by selecting an option for both ISP failure and ISP recovery.
Allowing Incoming and Outgoing Connections
14. To allow outgoing connections through both ISP links, define automatic Hide
NAT on network objects that initiate the outgoing connections. Using the
example shown in Figure 4-2 on page 142, configure the following:
a. Edit the internal_net object.
b. In the General tab of the Network Properties window, select Add Automatic
Address Translation Rules.
c. Select the Hide Translation Method and then the Hide behind Gateway option.
15. To allow incoming connections through both ISP links to the application servers
and the DNS server, define manual Static NAT rules.
If you have only one routable IP address from each ISP and those addresses
belong to the VPN-1 gateway, you can allow specific services for specific
servers. Using the example shown in Figure 4-2 on page 142, define the NAT
Chapter 4
ISP Redundancy 153
Configuring ISP Link Redundancy
rules listed in Table 4-1. In this example, incoming HTTP connections from
both ISPs reach the Web server, www.example.com and DNS traffic from both
ISPs reach the DNS server.
Table 4-1
Manual Static Rules for a Web Server and a DNS Server
Original
Translated
Comment
Source
Destination
Service
Source
Destination
Serv.
Any
192.168.1.2
http
=
10.0.0.2
(Static)
=
Incoming Web
ISP A
Any
172.16.2.2
http
=
10.0.0.2
(Static)
=
Incoming Web
ISP B
Any
192.168.1.2
domain
_udp
=
10.0.0.3
(Static)
=
Incoming DNS
ISP A
Any
172.16.2.2
domain
_udp
=
10.0.0.3
(Static)
=
Incoming DNS
ISP B
If you have a routable address from each ISP for each publicly reachable server
(in addition to the addresses that belong to the VPN-1 gateway), you can allow
any service to reach the application servers by giving each server a nonroutable
address. In the NAT Rule Base in Table 4-1, do the following:
a. Use the routable addresses in the Original Destination.
b. Use the nonroutable address in the Translated Destination.
c. Select Any as the Original Service.
Note - If using Manual NAT, automatic arp does not work for the NATed addresses.
On Linux and SecurePlatform use local.arp. On IPSO set up Proxy ARP.
16. Save and install the security policy.
Configuring the Default Route for the ISP
Redundancy Gateway
17. Configure the ISP Redundancy gateway machine with only a single default
route and do not give it a metric. When working in a Primary/Backup mode, set
the IP address of the router leading to the primary ISP as the default route.
When working in Load Sharing mode, use the router of the first ISP link in the
ISP Redundancy window as the default route.
154
Configuring ISP Link Redundancy
When an ISP link fails, the default route of the gateway is automatically changed
by means of the ISP Redundancy script. When the link is up again, the original
default route is reinstated.
Chapter 4
ISP Redundancy 155
Configuring ISP Link Redundancy
156
5
Chapter
ConnectControl - Server Load
Balancing
In This Chapter
The Need for Server Load Balancing
page 158
ConnectControl Solution for Server Load Balancing
page 159
Configuring ConnectControl
page 167
157
The Need for Server Load Balancing
The Need for Server Load Balancing
While Check Point offers optimal performance for single server deployment, there
are several disadvantages to relying on a single server to host an application. While
a server's capabilities can often be expanded with additional processors and RAM,
in many cases a lone machine cannot handle the traffic volume, which results in
poor response times and connection time outs. In addition, server maintenance and
other unplanned downtimes are problematic in a single server environment. Sharing
network traffic intelligently among multiple servers can shorten response times and
reduce the risk to the application by the failure of any one machine.
158
ConnectControl Solution for Server Load Balancing
ConnectControl Solution for Server Load
Balancing
In This Section
Introduction to ConnectControl
page 159
Load-Balancing Methods
page 160
ConnectControl Packet Flow
page 161
Logical Server Types
page 161
Persistent Server Mode
page 164
Server Availability
page 166
Load Measuring
page 166
Introduction to ConnectControl
ConnectControl is Check Point’s solution for server load balancing. ConnectControl
distributes network traffic among a number of servers, which reduces the load on a
single machine and thereby improves network response time and provides high
availability. In addition to the performance benefits, spreading the load over
multiple machines creates redundancy for your application and reduces the risk of
downtime.
Load-balanced servers are represented by a single virtual IP address, so clients are
unaware that more than one server is serving their requests. This is accomplished
using a Logical server, which is a network object defined in SmartDashboard that
represents a group of physical servers. The Logical server fields service requests for
the load-balanced application and directs them to the appropriate physical server.
ConnectControl runs on the gateway and does not impose any additional memory or
processing requirements. It continuously checks the availability of each server and
if a server fails or is unreachable, ConnectControl stops directing connections to
that server until it becomes available.
Chapter 5
ConnectControl - Server Load Balancing 159
ConnectControl Solution for Server Load Balancing
Load-Balancing Methods
ConnectControl distributes network traffic to load-balanced servers according to
predefined balancing methods, which include:
160
•
Server Load: Measures the load on each server to determine which server has
the most available resources to service a request. Each server in the group runs
a load measuring agent that automatically reports the current system load to
the ConnectControl module on the VPN-1 gateway. Server Load is a good choice
if your servers run other demanding applications in addition to supporting your
load-balanced application. For additional information, refer to “Load
Measuring” on page 166.
•
Round Trip: Ensures that incoming requests are handled by the server with the
fastest response time. ConnectControl ascertains the response times of the
servers in the group at a user-defined interval, whereupon the gateway executes
a series of ICMP echo requests (pings) and reports which server has the
shortest average round trip time. ConnectControl then directs the service
request to that server. The round trip method is a good choice if there are large
variations in the traffic load on your network or when load balancing over WAN
connections.
•
Round Robin: Assigns service requests to the next server in the sequence. The
round robin method provides optimal load balancing when the load balanced
servers all have similar RAM and CPU and are located on the same segment.
•
Random: Assigns service requests to servers at random. The random method
provides optimal load balancing when the load-balanced servers all have similar
RAM and CPU and are located on the same segment.
•
Domain: Directs service requests based on domain name.
ConnectControl Solution for Server Load Balancing
ConnectControl Packet Flow
When a client requests access to an application that is load balanced by
ConnectControl, the following is the packet flow (Figure 5-1):
1. A client initiates a connection with the logical IP address of the application
server, which is actually the address assigned to the Logical server.
2. The service request arrives at the gateway and is matched by the Logical server
rule in the Rule Base. VPN-1 then directs the packet to the Logical server.
3. ConnectControl determines which of the servers in the group can best fulfill the
request based on the load-balancing method.
Figure 5-1 ConnectControl Packet Flow
Logical Server Types
When creating the Logical server object, you must identify the server type as either
HTTP or Other. This distinction is important, as ConnectControl handles the
connection to the client differently for each server type. To direct network traffic,
the HTTP server type uses HTTP redirection, while the Other server type uses
address translation.
Chapter 5
ConnectControl - Server Load Balancing 161
ConnectControl Solution for Server Load Balancing
HTTP
The HTTP Logical server type employs HTTP redirection to distribute network traffic
and supports only HTTP services. The redirection mechanism ensures that all
sessions comprising an HTTP connection are directed to a single server. This is
critical for many web applications, such as those using HTTP-based forms, which
require that a single server process all user data.
The HTTP redirection mechanism works in conjunction with ConnectControl’s
load-balancing methods. The initial HTTP connection is directed to the proper
server based on the selected load-balancing method. ConnectControl then notifies
the client that subsequent connections should be directed to the IP address of the
selected physical server, rather than to the IP address of the Logical server. The IP
address can be the address of a server behind the firewall or of an offsite server.
The remainder of the session is conducted without ConnectControl intervention and
all operations are transparent to the user.
The Logical server may direct the client to an HTTP server behind the firewall or to
an offsite HTTP server (Figure 5-2), depending on the result of ConnectControl’s
load balancing.
Figure 5-2 Packet Flow in an HTTP Logical Server
All further communication between the client and the server takes place without
the intervention of ConnectControl.
162
ConnectControl Solution for Server Load Balancing
Other
The Other Logical server type can be used for all services supported by VPN-1
including HTTP. It uses NAT to direct network traffic to the grouped servers.
ConnectControl mediates each service request, even when clients continue a
session. When you create an Other Logical server type, ConnectControl allows the
connection by automatically placing entries in the VPN-1 kernel table.
ConnectControl determines which server receives the request and uses NAT to
modify the destination IP address of the incoming packet. If a return connection is
opened, the connection is automatically established between the server and the
client and the server’s source address in the packet is translated to that of the
Logical server. Figure 5-3 shows a connection being directed to a NATed FTP server
inside the firewall.
Figure 5-3 Packet Flow in an Other Logical Server type
On the packet’s return, the firewall translates the packet’s original address to that
of the Logical server.
You can also use an Other Logical server type to handle HTTP service requests. In
contrast to the HTTP type, once a connection between the client and server has
been established, the Other Logical server type does not disconnect. Instead,
ConnectControl handles each HTTP service request from the client and multiple
service requests from one client can be directed to different servers.
Considering Logical Server Types
When considering the proper implementation for your environment, there are three
decisive criteria: use of HTTP forms, server location and servers configured for NAT.
The HTTP type supports offsite HTTP servers and form based applications, but only
Chapter 5
ConnectControl - Server Load Balancing 163
ConnectControl Solution for Server Load Balancing
works with the HTTP protocol. The Other type supports all protocols and may
provide the most effectively balanced load, but requires servers to be NATed by the
gateway.
Persistent Server Mode
Persistent server mode is a ConnectControl feature that maintains a client’s
connection to the server to which it was first directed (for additional information,
refer to “Persistent Server Timeout” on page 165). When using this feature, you
must decide whether the persistency is by server or by service.
Persistency By Server
Persistency by server is useful for certain types of HTTP applications, such as
forms support, for example, in a load-balanced environment of three Web servers
(Figure 5-4). When Persistency by server is enabled, ConnectControl directs an
HTTP client to a specific server and each subsequent request by the client is
directed to the same server. This mode allows clients to fill out forms without the
data loss that occurs if separate service requests are directed to different servers. If
you support forms, enable Persistent server mode (the default setting) and the
Persistency by server option.
164
ConnectControl Solution for Server Load Balancing
Persistency By Service
The persistency by service feature is useful if you are load balancing multiple
services in your server group, for example, in a redundant environment of two
machines, each running HTTP and FTP (Figure 5-4).
Figure 5-4 Example of Persistency by Service
Using persistency by service, the client can be directed to one server for HTTP
services and another for FTP services. This prevents you from being locked in to a
server under a heavy load, as may occur if you opt for persistency by server in this
configuration. Persistency by service directs previously load-balanced clients, which
request a different service, to be load balanced and directed once again to the
correct server.
Persistent Server Timeout
The Persistent server timeout sets the amount of time that a client, once directed to
a particular server, continues to be directed to that server. In the event that a server
becomes unavailable, new connections are directed to an available server, even if
Persistent server mode is enabled. For optimal load balancing between servers,
disable Persistent server mode so that all application traffic is distributed according
to the load-balance method. The Persistent server timeout is configured in the
ConnectControl page of the Global Properties window.
Chapter 5
ConnectControl - Server Load Balancing 165
ConnectControl Solution for Server Load Balancing
Server Availability
You can configure various properties of ConnectControl in order to check the
availability of servers in the Logical server group. You can define how often the
module pings the servers to ensure they are still active and the number of attempts
it makes to contact a nonresponsive server after ConnectControl stops directing
connections to it.
These settings are located in the ConnectControl page of the Global Properties
window. The Server availability check interval option defines how often the servers
are pinged. The Server check retries option defines the number of attempts to
contact nonresponsive servers.
Load Measuring
The server load-balancing method is unique because it requires a load-measuring
agent to run on each server in the group. The agent is lightweight and does not add
additional latency or system overhead to the server. It uses the UDP transport
protocol to support communication between the load-measuring agent and the
ConnectControl module.
Check Point provides a sample load-measuring agent application for installation on
servers, as well as a load-measuring application programming interface (API) for
organizations who want to write their own agents. You can download the load agent
application for your OS from SecureKnowledge at:
https://support.checkpoint.com/login/login.jsp. Sign in with your User Center email
and password and enter the SecureKnowledge ID 47.0.1569467.2530820.
You can configure certain properties of the load-measuring agent in the
ConnectControl page of the Global Properties window. The Load agents port property
determines the port the load agent uses to communicate with VPN-1. All the
load-measuring agents in a configuration must use the same port number. The Load
measurement interval property defines the interval at which the agent returns
information about the server’s load to the firewall (the default is every 20 seconds).
For Windows servers, configure and enable the load-measuring agent using the
load_agent_nt <port_number> <load_value> syntax.
The default port used by ConnectControl for version NG or higher is 18212. The
values for load_value are 0, 1, 2, where:
• 0 measures the load over a 1 minute interval
• 1 measures the load over a 5 minute interval
• 2 measures the load over a 15 minute interval
166
Configuring ConnectControl
Configuring ConnectControl
To configure ConnectControl:
1. In SmartDashboard, right-click Network Objects in the Network Objects tree and
select New > Node > Host.
2. Define a server object that represents a load-balanced server.
3. Repeat step 2 for each server you place in the group.
4. In SmartCenter, right-click Network Objects and select New > Group > Simple
Group.
5. Name the group (for example, HTTP_Server_Group).
6. Add the server objects to the group in the Group Properties box. It is
recommended to add no more than 29 Logical servers to a group.
7. In SmartDashboard, right-click Network Objects in the Network Objects tree and
select New > Logical Server. Ensure the IP address you assign is a routable IP
address. All traffic to be load-balanced should be directed through the gateway.
8. Select the Server’s Type.
9. Add the Group object you created in step 3 to the Servers Group.
10. To enable Persistent server mode, select either Persistency by service or server
(the default mode is Persistency by service).
11. Select a load-balance method as the Balance Method.
12. Add the following rule (Table 5-1) to the Rule Base:
Table 5-1
Source
Destination
Service
Action
Any
Logical_Server
[load-balance
d service(s)]
Accept or
User Auth or
Client Auth or
Session Auth
13. For applications using HTTP redirection (HTTP Logical server type), add a
second rule to allow the physical server group to communicate directly with
clients after sessions have started (Table 5-2).
Table 5-2
Source
Destination
Service
Action
Any
HTTP_Server_Group
http
Accept
Chapter 5
ConnectControl - Server Load Balancing 167
Configuring ConnectControl
14. From the Policy menu, select Global Properties > ConnectControl. Review the
default settings and adjust according to your implementation. The following
options are available:
168
•
Servers Availability: Manages how often ConnectControl ensures that the
load-balanced servers are running and responding to service requests and
how many times ConnectControl attempts to contact a server before ceasing
to direct traffic to it. The Server availability check interval option default
value is 20 seconds. The Server check retries option default value is 3
times.
•
Servers Persistency: Defines the amount of time that a client, once directed
to a particular server, directs traffic to it. The Persistent server timeout
option default value is 1800 seconds.
•
Servers Load Balancing: Manages how often the load measuring agents (if
employed) report their load status to ConnectControl and the port from
which they communicate with ConnectControl. The Load agents port option
default value is 18212. The Load measurement interval default value is 20
seconds.
Chapter
Bridge Mode
6
In This Chapter
Introduction to Bridge Mode
page 170
Configuring Bridge Mode
page 172
169
Introduction to Bridge Mode
Introduction to Bridge Mode
Installing a new gateway in an existing network often requires reconfiguration of the
routing scheme. However, in more complex deployments, you may find that the
reconfiguration necessary to enable a new routing scheme is prohibitive. VPN-1
bridge mode allows for the placement of a firewall without changing the existing IP
routing.
A VPN-1 gateway in bridge mode operates as a regular firewall, inspecting traffic
and dropping or blocking unauthorized or unsafe traffic. A gateway in bridge mode
is invisible to all Layer-3 traffic. When authorized traffic arrives at the gateway, it is
passed from one interface to another through a procedure known as bridging.
Bridging creates a Layer-2 relationship between two or more interfaces, whereby
any traffic that enters one interface always exits the other. This way, the firewall
can inspect and forward traffic without interfering with the original IP routing.
Bridge mode allows a transparent deployment of a VPN-1 gateway. Figure 6-5
illustrates how a firewall in bridge mode does not alter the IP routing of an existing
network.
Figure 6-5 Deploying a Single VPN-1 gateway in bridge mode
In Figure 6-5 the subnet’s network address is 192.168.1.0 and objects labeled S-*
are switches.
In terms of IP routing, the firewall is transparently inserted into the existing
network, leaving the 192.168.1.0 subnet on both sides of the firewall. Internal
traffic is inspected and authorized by the firewall, without changes to the IP
routing scheme. Traffic that is accepted by the firewall is forwarded from one
interface to the other.
For additional configuration information, refer to “Bridging Interfaces” on
page 172.
170
Limitations in Bridge Mode
Limitations in Bridge Mode
•
Each bridge supports a pair of interfaces only.
•
Cluster configurations are not supported.
•
Bridge mode is supported on the Check Point operating system SecurePlatform.
Managing a Gateway in Bridge Mode
In order to manage a gateway in bridge mode, an interface with an IP address is
required. It is important to configure a separate, routed interface for this purpose.
Chapter 6
Bridge Mode 171
Configuring Bridge Mode
Configuring Bridge Mode
Bridging Interfaces
You can bridge interfaces using either the SecurePlatform WebUI, or from the
command line.
Using the SecurePlatform WebUI:
1. Connect to the management interface of the VPN-1 gateway using WebUI.
2. Select Network > Connections > New > Bridge.
3. Select the interfaces to comprise the bridge and click Add.
4. Enter the IP Address and Netmask of the bridge (not the physical) interface, or
assign IP address 0.0.0.0 for a bridge without an IP address. Note that while a
bridge can function without an IP address, some security servers require an IP
address on the relevant subnet.
5. Select Apply.
From the Command Line:
1. Enter the command sysconfig.
2. Select Network Connections > Add new connection > Bridge.
3. Add a pair of interfaces which are not configured with an IP address to the
bridge.
4. Enter N for next.
5. Enter the IP address and netmask of the bridge (not the physical) interface, or
assign IP address 0.0.0.0 for a bridge without an IP address. Note that while a
bridge can function without an IP address, some security servers require an IP
address on the relevant subnet.
Configuring Anti-Spoofing
When bridging interfaces, it is not possible to define the network behind a bridged
interface by IP address and subnet, since this is true for the other interface of the
bridge. If anti-spoofing is required for the bridged interfaces, see “Defining
Addresses for Internal Interfaces” on page 49 for instructions on defining IP
addresses ranges behind each of the bridged interfaces. Do not use the same
network for both interfaces, as this may cause a loss of connectivity.
172
Displaying the Bridge Configuration
Displaying the Bridge Configuration
brctl show
The brctl show command displays the status of the bridge configuration. The
following is an example of a brctl show command report:
[Expert@GW-1]# brctl show
bridge name
br0
bridge id
8000.000423b93e56
STP enabled
no
interfaces
eth0 eth1
The brctl show command report displays the following results:
•
bridge name: The name given to the bridge.
•
bridge id: The unique identifier of the bridge.
•
Interfaces: The names of the two interfaces in the bridge.
The MAC address of the bridge is inherited from one of the physical interfaces.
Chapter 6
Bridge Mode 173
Displaying the Bridge Configuration
174
SmartDefense
This section gives a conceptual overview of SmartDefense, which enables
customers to configure, enforce and update network and application attack
defenses. The DShield StormCenter is also described in detail. For information
about specific protections, see the SmartDefense HTML pages and the online
help.
Chapter
SmartDefense
7
In This Chapter
The Need for SmartDefense
page 178
SmartDefense Solution
page 180
Network Security
page 188
Application Intelligence
page 195
Web Intelligence
page 198
Configuring SmartDefense
page 210
SmartDefense Services
page 211
Configuring SmartDefense Profiles
page 214
SmartDefense StormCenter Module
page 216
177
The Need for SmartDefense
The Need for SmartDefense
The threats to your organization’s network security are many and are constantly
evolving (Figure 7-1).
Figure 7-1 Network Attacks
Since firewall access control solutions such as VPN-1 prevent unauthorized traffic
from passing through most gateways, hackers tend to focus on the misuse of
permitted traffic and services. Some of the most serious threats in today's Internet
environment come from attacks that attempt to attack the application layer. Of
particular interest to hackers are TCP/IP services such as HTTP (port 80) and
HTTPS (port 443) because they, of necessity, remain open in most networks.
Attacks on these services are difficult for access control devices to detect.
The following two examples describe typical Denial of Service (DoS) attacks that
exploit HTTP vulnerability. In the first scenario, you decide to allow ICMP requests
(pings) on your network. A DoS attack can exploit this vulnerability by flooding your
network with pings, thereby preventing other connections. If you do not have a
defense that automatically detects and prevents this kind of attack, you would be
forced to disallow pinging, which is not an ideal solution.
178
The Need for SmartDefense
In the second scenario, SYN attacks disrupt TCP/IP traffic by sending SYN packets
and then not acknowledging the TCP/IP server response packet. This causes the
server to keep signaling until it eventually times out. This is a problem because
disabling TCP/IP is not an option. There are other solutions available, such as
content security applications (virus scanners), but these applications are
inadequate because they are limited to specific services and they are unable to
detect patterns of hacker activity.
Securing your network with up-to-date detection methods that prevent attacks is
critical to safeguarding your organization’s data and communications.
SmartDefense is the only solution that addresses such threats in a reliable and
effective manner. The following sections describe the SmartDefense solution to the
ever evolving nature of attacks on the network perimeter.
Chapter 7
SmartDefense 179
SmartDefense Solution
SmartDefense Solution
In This Section
Introducing SmartDefense
page 180
Defending Against the Next Generation of Threats
page 181
Network and Transport Layers
page 182
Web Attack Protection
page 182
How SmartDefense Works
page 183
Categorizing SmartDefense Capabilities
page 184
SmartDefense Profiles
page 186
Monitor-Only Mode
page 187
Introducing SmartDefense
SmartDefense is an integral part of VPN-1, providing a unified security framework
that identifies and prevents attacks. SmartDefense defends your network even if
protection is not explicitly defined in the Rule Base. It unobtrusively analyzes
activity across your network, tracking potentially threatening events and sending
notifications. It protects organizations from all known, and most unknown, network
attacks using intelligent security technology. A single click allows you to update
SmartDefense with the latest defenses from the SmartDefense website.
SmartDefense protection is fully customizable allowing you to:
•
Select the attacks that you want to protect your network against and receive
detailed information on those attacks.
•
Configure parameters for each attack, including logging options.
•
Receive real time information on attacks and update SmartDefense with new
the latest features and capabilities.
The SmartDefense page in the SmartDashboard window has a tree-structured
navigation pane that classifies protections into several categories: “Network
Security”, “Application Intelligence” and “Web Intelligence”.
Note - When updating SmartDefense, new categories, as well as attack defenses, may be
added to the tree structure.
180
SmartDefense Solution
Defending Against the Next Generation of Threats
A growing number of attacks attempt to exploit vulnerabilities in network
applications rather than targeting the firewall directly. Application Intelligence is a
set of advanced capabilities, integrated into VPN-1 and SmartDefense that detects
and prevents application layer attacks (Figure 7-2). Based on the INSPECT
intelligent inspection technology, Application Intelligence gives SmartDefense the
ability to protect against application attacks and hazards.
Figure 7-2 OSI (Open Systems Interconnection) Reference Model
Note - The OSI Reference Model is a framework, or guideline, which describes how data is
transmitted between devices on a network.
The Application Layer is not the actual end-user software application, but a set of services that allow
the software application to communicate through the network. Distinctions between layers 5, 6, and 7
are not always clear, and some competing models combine these layers, as does this administration
guide.
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SmartDefense 181
SmartDefense Solution
Network and Transport Layers
Application Intelligence works primarily with application layer defenses. However,
in practice, many attacks aimed at network applications actually target the network
and the transport layers.
Hackers target these lower layers as a means to access the application layer, and
ultimately the application and its data. In addition, by targeting lower layers,
attacks can interrupt or deny service to legitimate users and applications (for
example, DoS attacks). For these reasons, SmartDefense addresses not only the
application layer, but also the network and transport layers.
Preventing the manipulation of network-layer protocols (for example, IP and ICMP)
is a crucial requirement for multilevel security gateways. The most common vehicle
for attacks against the network layer is the Internet Protocol (IP), whose set of
services resides within this layer.
As with the network layer, the transport layer and its common protocols (for
example, TCP and UDP) provide popular access points for attacks on applications
and their data.
Web Attack Protection
Web servers and web applications have evolved from their origins as serving simple
static content. Today, Web servers and applications can create dynamic pages,
invoke other applications, and communicate with databases to produce useful
content for users. With most Web server platforms bundling applications with the
server, even the simplest web sites interact with web applications.
Figure 7-3 Multiple Security Vulnerabilities in the N-Tier Web Architecture
With almost all organizations allowing web traffic (TCP port 80) through their
perimeter firewall, hackers are increasingly focusing their attacks on Web servers
and applications. Many attacks today exploit security weaknesses in the different
layers of web architecture. These attacks include defacing the primary web
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interface, getting an embedded web application on a server to do unintended
functions, installing malicious applications and tricking the backend database to
send information back to the user.
Like network security, web security is only as strong as the weakest link. To build
secure web applications, web developers must build security into every aspect of
the application. Unfortunately, many enterprise web applications are not designed
with holistic security in mind. Even worse, an organization may incorporate web
security into only some of the Web servers that are accessible to the outside world.
Web Intelligence pages enables customers to configure, enforce and update attack
protections for Web servers and applications. Web Intelligence protections are
designed specifically for web-based attacks, and complement the network and
application level protections offered by SmartDefense. In addition, Web Intelligence
Advisories, published online by Check Point, provide information and add new
attack defenses.
Web Intelligence not only protects against a range of known attacks, but also
incorporates intelligent security technologies that protect against entire categories
of emerging or unknown attacks. Unlike web firewalls and traditional intrusion
protection systems, Web Intelligence provides proactive attack protections. This
ensures that communication between clients and Web servers complies with
published standards and security best practices, restricts hackers from executing
irrelevant system commands, and inspects traffic passing to Web servers to ensure
that it does not contain malicious code. Web Intelligence allows organizations to
permit access to their Web servers and applications without sacrificing either
security or performance.
How SmartDefense Works
SmartDefense is integrated into VPN-1. As all inbound traffic is routed through the
firewall, as this is the logical place for active defenses to reside. Some
SmartDefense capabilities are enforced at the network boundary, while others, such
as Abnormal Behavior Analysis, are managed from the SmartCenter server. The
SmartDefense protections are distributed as part of the security policy to each
gateway from the SmartCenter server. SmartDefense blocks attacks at the network
boundary using Check Point's Stateful Inspection technology.
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Online Updates
Customers who purchase the SmartDefense subscription service can automatically
update SmartDefense with a single click. Updates are released frequently, and can
be obtained from the Check Point SmartDefense site:
http://www.checkpoint.com/techsupport/documentation/smartdefense/index.html
Customers with a valid subscription license also receive special SmartDefense
Advisories that provide updated SmartDefense attack protections, as well as
information, tools and best practice methods to mitigate different attacks.
Tip - It is recommended to keep your gateway version up-to-date, as the newest
defenses are incorporated into the latest version of Check Point software.
Categorizing SmartDefense Capabilities
SmartDefense protects your organization against attacks and other illegitimate or
unwanted network activity using the following categories of SmartDefense
capabilities:
•
“Defense Against Attacks” on page 184.
•
“Information Disclosure Prevention” on page 185.
•
“Abnormal Behavior Analysis” on page 185.
Some SmartDefense features provide more than one category of protection. For
example, the Initial Sequence Number Defender (ISN Defender) defends against
both the specific attack and Implicit Defense.
Defense Against Attacks
SmartDefense protects organizations from known and unknown network attacks.
Attacks are stopped at the gateway and are prevented from affecting the target
server. SmartDefense is easy to configure, and defends against attacks while
freeing the administrator from the need to understand the technical details of the
attack.
SmartDefense protects your network against the following types of attacks:
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•
Denial of Service Attacks
•
TCP/IP Attacks
SmartDefense Solution
•
Web and Application Vulnerabilities
•
Network Probing
•
HTTP Worms
For example, consider a TCP/IP attack called ISN Guessing. TCP/IP connections are
initiated by way of a three-way handshake: the client sends a SYN packet, the
server replies with a SYN/ACK and the client sends an ACK packet to acknowledge
the connection. With each SYN/ACK, the server also generates an initial sequence
number (ISN or SN) that identifies the connection. The SNs are generated using a
key, and in some operating systems you can guess the next SN based on the
previous SN. If an external client successfully guesses the next valid SN, it can
then open a connection to the server by sending a SYN/ACK packet with a valid SN.
This connection could be from a nonexistent IP address and may carry damaging
data.
SmartDefense fends off this type of attack by replacing the server as the SN
generator and using an encrypted key to generate SNs less susceptible to attack.
Information Disclosure Prevention
Implicit Defense prevents information on network entities from reaching the
Internet, where the information could be misused.
Using the SN vulnerability example in “Defense Against Attacks” on page 184,
when an internal server establishes a TCP connection, it sends successive SNs.
Under certain conditions, these SNs can be used to identify the source’s operating
system. SmartDefense uses fingerprint spoofing to replace one fingerprint with
another, thereby making it impossible for external clients to discover the operating
system used by the internal servers.
Abnormal Behavior Analysis
SmartDefense analyzes patterns of abnormal network behavior. It detects these
patterns by analyzing logs sent to the SmartCenter server by the VPN-1 gateways. If
a suspicious pattern is detected, the administrator can track the activity using a log
or an alert (depending on the configuration setting).
Using the Port Scan detection feature, whenever SmartDefense detects port
scanning, it logs the activity and issues an alert.
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SmartDefense Profiles
Since there are many different kinds of threats to your network’s security, different
gateways may require different configurations in order to guard against the
increasing number and variety of threats. SmartDefense Profiles enable the
administrator to customize the SmartDefense protection according to the needs of
each gateway in the community. A SmartDefense Profile may be installed on more
than one gateway.
The following features are configured universally for all gateways:
•
Spoofed Reset Protection: The services exclusion list, which is applied globally
(not per profile).
•
Successive Events: The settings relevant for log servers and not for each
gateway.
•
DShield Storm Center (Report to DShield): The settings that are not part of the
firewall and therefore cannot have different settings.
•
Definitions of patterns (worm catcher patterns, P2P/IM patterns): The definition
is global and each pattern can be activated/deactivated in each profile.
If you do not specify a profile to a gateway, the default profile is assigned.
Up to 20 profiles may be created. SmartDefense Profiles are available for all NGX
R60 gateways and above.
For Connectra, SmartDefense Profiles are available for all NGX R62CM gateways
and above. Earlier versions of Connectra gateway do not receive a SmartDefense
profile from SmartCenter.
Note - Every profile created takes 2 MB of RAM from the user console machine on both
Windows and Motif.
To configure SmartDefense Profiles refer to “Configuring SmartDefense Profiles” on
page 214.
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Monitor-Only Mode
Many protections have a monitor-only option, which detects and tracks
unauthorized traffic without blocking it (refer to Figure 7-4). Intrusions are logged
in SmartView Tracker.
Figure 7-4 Protection Scope and Action Settings
The monitor-only option is helpful when deploying a protection for the first time, in
order to evaluate the effectiveness of the protection without interrupting
connectivity. Monitor-only mode also enables audit-only deployment.
Special Monitor-Only Mode
When all active protections are in monitor-only mode, connections that contain
non-HTTP compliant data are not rejected. In this special mode, SmartDefense
does not affect traffic at all. In contrast, when only some of the active protections
are in monitor mode-only, non-HTTP compliant traffic is rejected.
This special operating mode is especially helpful when deploying SmartDefense for
the first time, to evaluate its effectiveness without interrupting connectivity, or
when troubleshooting a problem that is related to blocking traffic.
Monitor-Only Per Web Server
All protections on a particular Web server can be set to monitor-only. This makes it
possible to put a new Web server in place and investigate which protections it
needs, while ensuring that connectivity is maintained.
To configure a monitor-only per Web server, use the Check Point Database Tool
(GUIdbedit, located in the SmartConsole installation directory). Using GuiDBedit,
search for the Web server name, and then set the web_server_monitor_only field to
TRUE.
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Network Security
From the Network Security pages, you can configure various SmartDefense
protections against attacks on the network and transport levels. Such attacks,
which occur on the IP, TCP, UDP or ICMP network protocols, range from the
identification of your organization’s operating systems to denial of service attacks
on hosts and servers on the network. Each SmartDefense protection is accompanied
by a corresponding description of the attack.
Japanese Language Support for SmartDefense
Protections
When SmartConsole detects the underlying operating system to be Japanese
enabled, it displays the description pages for each SmartDefense protection in
Japanese.
This behavior can be controlled via a new property in the database: gui_client_lang
as shown in Figure 7-5:
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Figure 7-5
Language display options for SmartDefense protections
SmartDefense Single Profile View
By running Fwpolicy.exe with the /G flag or by making TRUE the
sd_enable_single_profile_mode property in GuiDBedit, you can display a simpler
view of your SmartDefense protections. A view where:
•
The icons in the navigation tree show the status of the protection (where
available)
•
Profile-selection, summary list, global actions per protection, and protection per
profile sections are not displayed.
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Denial of Service
Denial of Service (DoS) attacks are designed to overwhelm the target with spurious
data to the point where it is no longer able to respond to legitimate service
requests. These attacks exploit operating system bugs, which can remotely disable
servers. For additional information, refer to the SmartDefense help pages and
online help.
Aggressive Aging
Aggressive Aging manages the connections table capacity and the memory
consumption of the firewall in to order to increase durability and stability.
Aggressive Aging uses a new set of short timeouts called aggressive timeouts. When
a connection is idle for longer than its defined aggressive timeout, it is marked as
eligible for deletion. When the connections table or memory consumption reaches a
certain user defined threshold (highwater mark), Aggressive Aging begins to
operate. Table 7-1 provides a list of aggressive aging timeout default values.
Table 7-1
Aggressive Aging Timeouts
IP Protocol/State
Aggressive Timeout
Timeout
TCP Start Session
5
25
TCP Session
600
3600
TCP End Session
3
20
UDP
15
40
ICMP
3
30
IP Protocol - HTTP
60
3600
Other (these protocols
are not enforced by
default)
15
60
Note - For all http related services (i.e., http, https, http_proxy_8080), aggressive aging
timeout is 60 seconds by default.
Aggressive Aging timeouts are also configurable per service.
Once the defined threshold is exceeded, each incoming connection triggers the
deletion of ten connections from the eligible for deletion list. An additional ten
connections are deleted with every new connection until the memory consumption
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or the connections capacity falls below a certain low watermark. If there are no
"eligible for deletion" connections, no connections are deleted at that time but the
list is checked after each subsequent connection that exceeds the highwater mark.
Timeout settings are a key factor in memory consumption configuration. When
timeout values are low, connections are deleted faster from the table, enabling the
firewall to handle more connections concurrently. When memory consumption
exceeds its threshold, it is best to work with shorter timeouts that can maintain the
connectivity of the vast majority of the traffic.
The major benefit of Aggressive aging is that is starts to operate when the machine
still has available memory and the connections table is not entirely full. This way,
it reduces the chance to encounter connectivity problems that might have occurred
under low resources conditions.
Aggressive Aging allows the gateway machine to handle large amounts of
unexpected traffic, especially during a DoS attack.
If a SecureXL device does not support Aggressive Aging, then the feature is
disabled. When this happens, the action is logged and a console message is
generated. All SecureXL NGX R65 devices support Aggressive Aging.
IP and ICMP
IP and ICMP provides a comprehensive sequence of layer three tests for the IP and
ICMP protocols. For example, the Fragmentation Timeout Logs feature generates
logs when it detects packets that have been fragmented for a firewall bypassing or
a DoS attack. For additional information, refer to the SmartDefense help pages and
online help.
TCP
VPN-1 can identify the basic IP based protocols and analyze a packet in order to
verify that it only contains permitted options. The following tests are conducted to
verify that TCP packets are legitimate:
•
Protocol type verification
•
Protocol header analysis
•
Protocol flags analysis and verification
SYN Attack Protection prevents attacks in which TCP connection initiation packets
are sent to the server in an attempt to cause denial of service.
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The Sequence Verifier is a mechanism that matches the current TCP packet
sequence number to the TCP connection state. Packets that match the connection
in terms of the TCP session but have incorrect sequence numbers are either
dropped or stripped of data. For additional information, refer to the SmartDefense
help pages and online help.
Fingerprint Scrambling
It is sometimes possible to identify a machine’s operating system or to impersonate
an existing connection with a fingerprint that identifies the operating system or the
connection. The SmartDefense Fingerprint Scrambling feature prevents this by
distorting the fingerprint in order to make identification impossible. For additional
information, refer to the SmartDefense help pages and online help.
Successive Events
The Successive Events feature detects malicious or suspicious events and notifies
the security administrator. Successive Events detection runs on the SmartCenter
server and analyzes logs from VPN-1 gateways by matching log entries to attack
profiles. The security administrator can modify attack detection parameters,
enable/disable detection for specific attacks or disable the Successive Events
feature.
Logs that do not reach the SmartCenter server (for example, local logs and logs
sent to the Log server) are not analyzed. For additional information, refer to the
SmartDefense help pages and online help
DShield Storm Center
Storm Centers gather logging information on attacks. This information is voluntarily
provided by organizations worldwide for the benefit of all. Storm Centers collate
and present reports on real-time threats to network security.
The SmartDefense Storm Center Module updates your organization with the latest
attack information from other Storm Centers and allows you to contribute your
attack logs to their databases.
One of the leading Storm Centers is SANS DShield.org. SmartDefense integrates
with the SANS DShield.org Storm Center in the following ways:
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•
The DShield.org Storm Center produces a Block List report, which is a list of
address ranges that are recommended for blocking. This list is frequently
updated. The SmartDefense Storm Center Module retrieves and immediately
adds this list to the security policy.
•
Sending logs to the Storm Center to help other organizations combat threats
that were directed at your network. You can decide which logs to send by
selecting the rules for which you want to send logs.
For additional information on SmartDefense DShield Storm Center integration, refer
to “SmartDefense StormCenter Module” on page 216.
Port Scan
Port Scanning is an information collection method for open TCP and UDP ports in
a network. Although the collection of information does not in itself constitute an
attack, this information can be used later to target and attack vulnerable
computers.
In order to offer a service to another computer, a host must open a port for that
service. Ports often remain open in default installations, unbeknownst to the
administrator, leaving the host vulnerable to attack. For example, if the FTP service
is left open by default, an attacker can try to guess the default username and
password in order to gain access to the machine. Port scanning can be performed
either by a hacker using a scanning utility, or by a worm attempting to spread to
other computers. Port scanning is most commonly performed by trying to access a
port and waiting for a response, whereby the response indicates whether or not the
port is open.
The SmartDefense Port Scanning feature does not block the scanning, but detects
ports scans with one of three levels of detection sensitivity. When a port scan is
detected, a log or an alert is issued.
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You can block clients that SmartDefense detects as sources of port scanning by
configuring automatic SAM (Suspicious Activity Monitoring) alert rules on the
SmartCenter server to block the offending IP addresses. For additional information
on the sam_alert command, refer to the Command Line Interface (CLI)
Administration Guide.
Warning - An automatic sam_alert rule may expose legitimate hosts to a remote DoS
attack. An attacker could spoof a port scan from a legitimate IP, which would then be
blocked by the automatic SAM rule.
For additional information, refer to the SmartDefense help pages and online help.
Dynamic Ports
A number of services (such as FTP under heavy load and SIP protocols) can set up
connections by opening ports dynamically. These ports can turn out to be the same
as those used by one of the predefined services in SmartDashboard. From the
Dynamic Ports page, you can define whether to drop a connection with a
dynamically opened port that is the same as a predefined service port. You can also
decide whether to drop dynamic port connections that use low port numbers (below
1024). For additional information, refer to the SmartDefense help pages and online
help.
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Application Intelligence
Application Intelligence pages allow you to configure various protections at the
application layer.
Mail
The SMTP security server enables strict enforcement of the SMTP protocol. It
protects against malicious mail messages, provides SMTP protocol centered
security, prevents attempts to bypass the Rule Base using mail relays, and prevents
Denial of Service and spam mail attacks. Normally, the security server is activated
by specifying resources or authentication rules in the Security Rule Base.
You can define which types of enforcement are applied to SMTP connections
passing through the security server. The Configuration applies to all connections
option forwards all SMTP connections to the SMTP security server and enforces the
defined settings on all connections without having to define a resource in the Rule
Base. The Configurations apply only to connections related to Rule Base defined
objects option only applies these configurations to SMTP connections for which a
resource is defined in the Rule Base.
For additional information, refer to the SmartDefense help pages and online help.
FTP
You can configure various protections related to the FTP protocol. For example,
preventing FTP port overflow checks and foils any attempt to use an FTP server as
an agent for a malicious operation.
For additional information, refer to “FTP Security” on page 333 and the
SmartDefense help pages and online help.
Microsoft Networks
You can configure various protections at the application layer, using SmartDefense's
Application Intelligence capabilities. For additional information, refer to “Microsoft
Networking Services (CIFS) Security” on page 329 and the SmartDefense help
pages and online help.
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Peer-to-Peer
SmartDefense can block peer-to-peer traffic by identifying the proprietary protocols
and preventing the initial connection to the peer to peer networks. This not only
prevents, but also search operations. SmartDefense can identify the protocol even if
the peer to peer application switches port numbers. The detection does not, for
example, rely on identifying HTTP header signatures. For additional information,
refer to the SmartDefense HTML pages and online help.
Instant Messengers
You can block Instant Messaging applications that use VoIP protocols. Instant
Messaging applications have many capabilities, including voice calls, message
transfer and file sharing. For additional information, refer to the SmartDefense
HTML pages and online help.
DNS
The DNS protocol identifies servers by their IP addresses and aliases. DNS protocol
messages can be transported over TCP or UDP. This option verifies that all the
connections on the DNS port over UDP are DNS related. In addition, certain
restrictions are imposed on the type of data allowed in queries and answers. For
additional information, refer to the SmartDefense HTML pages and online help.
VoIP
Voice and video traffic must to be protected as it enters and leaves a network.
Potential threats to voice and video traffic are:
•
Call redirections whereby calls intended for one recipient are redirected to
another.
•
Stealing calls, where the caller pretends to be someone else.
•
System hacking using ports opened for VoIP connections.
VoIP calls involve a series of complex protocols, each of which can carry potentially
threatening information through many ports.
SmartDefense ensures that caller and recipient addresses are valid and that the
caller and recipient can make and receive VoIP calls. SmartDefense also examines
the contents of the packets passing through every allowed port to ensure that they
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contain the proper information. Full stateful inspection on H.323, SIP, MGCP and
SCCP commands ensures that all VoIP packets are structurally valid and that they
arrive in a valid sequence.
For additional information, refer to “Securing Voice Over IP (VoIP)” on page 247.
SNMP
SmartDefense enables you to protect against SNMP vulnerabilities by providing the
option of enforcing SNMPv3 (the latest SNMP version) while rejecting previous
versions. In addition, SmartDefense can allow all SNMP versions while dropping
requests with SNMPv1 and SNMPv2 default community strings. Monitor-only mode
enables you to track unauthorized traffic without blocking it. For additional
information, refer to the SmartDefense HTML pages and online help.
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Web Intelligence
In This Section
Web Intelligence Protections
page 198
Web Intelligence Technologies
page 199
Web Intelligence and ClusterXL Gateway Clusters
page 199
Web Content Protections
page 200
Customizable Error Page
page 200
Connectivity Versus Security Considerations
page 201
Web Security Performance Considerations
page 203
Backward Compatibility Options for HTTP Protocol Inspection
page 205
Web Intelligence License Enforcement
page 205
Understanding HTTP Sessions, Connections and URLs
page 207
Web Intelligence focuses on protecting Web servers against attacks. As such, Web
server objects are defined, and protections are applied either to all Web servers or
to selected Web servers. Any gateway or host object can be defined as a Web
server.
Web Intelligence Protections
Web Intelligence protections are organized into a number of protection classes
Malicious Code
These protections prevent attacks that attempt to run malicious code on Web
servers .
Application Layer
This class of protection prevents hackers from introducing text, tags, commands, or
other characters that a web application will interpret as special instructions.
Introducing such objects into forms or URLs can allow a hacker to steal private
data, redirect a communication session to a malicious web site, steal information
from a database, gain unauthorized access, or execute restricted commands.
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Information Disclosure
These protections prevent an attacker from gathering information about a web site.
The goal of information disclosure is to obtain information from the Web server that
can be used to tailor an attack.
HTTP Protocol Inspection
HTTP Protocol Inspection provides strict enforcement of the HTTP protocol,
ensuring that sessions comply with RFC standards and common security practices.
Web Intelligence Technologies
Web Intelligence is based on Check Point's Stateful Inspection, Application
Intelligence, and Malicious Code Protector technologies, so that it is possible to
block not only specific attacks, but also entire categories of attacks, while allowing
legitimate traffic to pass.
•
Malicious Code Protector is a Check Point patent-pending technology that
blocks hackers from sending malicious code to target Web servers and
applications. It can detect malicious executable code within web
communications by identifying not only the existence of executable code in a
data stream but its potential for malicious behavior. Malicious Code Protector is
a kernel-based protection delivering almost wire-speed performance.
•
Application Intelligence is a set of technologies that detect and prevent
application-level attacks by integrating a deeper understanding of application
behavior into network security defenses.
•
Stateful Inspection analyzes the information flow into and out of a network so
that real-time security decisions are based on communication session
information as well as on application information. It accomplishes this by
tracking the state and context of all communications traversing the firewall
gateway, even when the connection involves complex protocols.
Web Intelligence and ClusterXL Gateway Clusters
Web Intelligence features on a ClusterXL gateway cluster do not survive failover.
This means that if ClusterXL is providing Web Intelligence protections and a cluster
member fails, HTTP connections passing through the failed member are lost.
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Web Content Protections
VPN-1 provides Web Content Security via its OPSEC partners. This allows URL
filtering and Network Virus Protection using Check Point best-of-breed partners. For
details, refer to “Content Security” on page 339.
VPN-1 also provides a number of integrated web security capabilities that are
configured via the Security Rule Base. These include a number of URL-based
protections, and the ability to secure XML Web Services (SOAP) on Web servers.
For details, refer to Chapter 15, “Web Content Protection”.
Customizable Error Page
Many Web Intelligence protections allow the administrator to define an error page
that can be sent back to the user whose browsing was blocked (refer to Figure 7-6).
This page can be used (in conjunction with SmartView Tracker) to pinpoint the
exact reason that caused the connection to be closed.
Figure 7-6 HTML Error Page Configuration
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This makes it possible to quickly nail down and eliminate the attack, before it can
spread. The security administrator can fix the problem even before users know
about it, or if the users notice the problem first, they can call the Help Desk about
it. Alternatively, users can be given information in the web page about how to fix
the problem themselves, which is of great benefit to overworked support staff.
The administrator can customize the page to include text and a logo. To help
pinpoint the reason that caused the connection to be closed, the page shows two
IDs: a Reject ID and an Error Description ID.
Note - Activating the Error Page decreases performance for Web traffic to which this feature is applied.
Reject ID
The Reject ID that appears on the error page is intended to deliver information to
the administrator without exposing it to a potential attacker.
The Reject ID is unique for each rejected connection. The Reject ID also appears
in the SmartView Tracker and allows the administrator to correlate between an error
and a log record of a specific connection. The log record contains attack
information, such as “Cross site scripting detected”.
Error Description ID
The Error Description ID is a standard ID that is used to identify the attack. It
appears in the SmartView Tracker log and corresponds to a SecureKnowledge
solution about the attack. For example, the following could appear in the
Information column of the SmartView Tracker log: “WSE0030002 cross site
scripting detected in request”. The WSE0030002 is the Error description ID, and
a SecureKnowledge search for that ID will locate information about the attack.
The administrator can decide whether or not to display the Error Description ID on
the error page. Due to the potential for misuse by an attacker, it is recommended
that you do not display this information .
Connectivity Versus Security Considerations
Web Intelligence can be tuned for greater Web server security at the expense of
connectivity, or vice versa.
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Monitor-Only Mode
All Web Intelligence protections have a monitor-only mode which makes it possible
to evaluate how the protection will affect connectivity, by examining logs to spot
traffic that Web Intelligence has detected as being dangerous. All this, while
allowing uninterrupted traffic flow.
Protection for Specific Servers
All Web Intelligence defenses can be activated for specific Web servers. If the
protection is problematic on a particular Web server, it can be turned off for that
specific Web server.
Variable Security Levels
Some of the advanced defenses (Cross Site Scripting, Command Injection, SQL
injection and Malicious Code Protector) have variable security level settings. If a
connectivity problem arises on a specific Web server, the security level can be
lowered for that Web server.
Connectivity Implications of Specific Protections
HTTP protocol inspection settings that are too severe can affect connectivity to and
from valid Web servers.
•
HTTP Format sizes protection restricts URL lengths, header lengths or the
number of headers. This is good practice because these elements can be used
to perform a Denial of Service attack on a Web server. At the same time, these
restrictions can potentially block valid sites. Applying the protection for specific
Web servers can solve the connectivity problems.
•
ASCII only Request Header protection can block connectivity to web pages that
have non-ASCII characters in URLs. Applying the protection for specific Web
servers can solve the connectivity problems.
HTTP methods - Some standard and non-standard HTTP methods are unsafe,
because they can be used to exploit vulnerabilities on a Web server. Microsoft
WebDAV methods (used for Outlook Express access to Hotmail), for example, have
certain security issues, but blocking them can prevent the use of important
applications. Applying the protection for specific Web servers can solve the
connectivity problems.
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Web Security Performance Considerations
In This Section
Protections Implemented in the Kernel Vs. Security Server
page 203
Protections with a Higher Performance Overhead
page 204
Adjusting the Number of Allowed Concurrent HTTP Connections page 204
Protections Implemented in the Kernel Vs. Security
Server
Web Intelligence provides a wide range of security features for Web servers. All Web
Intelligence features are implemented in the kernel Inspection Module, which
means that users benefit from very high performance.
VPN-1 provides a number of web security capabilities that do not require the Web
Intelligence feature. These capabilities make use of the HTTP Security Server. The
performance provided by the HTTP Security Server is not as high as that provided
by the kernel. These capabilities are available by defining a URI Resource and
using it the Security Rule Base. They are listed in Table 7-2.
Table 7-2
Web Security Capabilities Not Requiring the Web Intelligence feature
Web Security Capability
Refer to
Integration with CVP servers for Anti-Virus protection.
“CVP Servers for Anti-Virus and Malicious Content Protection” on
page 344.
URL filtering (via a UFP server) with
enhanced security checks.
“Using URL Filtering to Limit Web
Surfers” on page 348
Blocking URL-based attacks by source
and destination
“Filtering URLs, Schemes and Methods by Source and Destination” on
page 379.
Integrated URL filtering of a limited
list of sites.
“Basic URL Filtering” on page 380
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Table 7-2
Web Security Capabilities Not Requiring the Web Intelligence feature
Web Security Capability
Refer to
HTML weeding: Stripping script tags,
Applet tags, ActiveX, FTP links and
port Strings.
“Java and ActiveX Security” on
page 381.
HTTP Response scanning: Blocking
Java Code.
“Java and ActiveX Security” on
page 381
Securing XML Web Services (SOAP).
“Securing XML Web Services (SOAP)”
on page 382.
Protections with a Higher Performance Overhead
Web Intelligence default protections are optimized to blend high security and
performance.
Activating the following features decreases performance for the web traffic to which
these features are applied:
•
Custom HTML error pages.
•
Header Spoofing, where headers are rewritten.
•
ASCII Only Response Headers, where the HTTP response is inspected.
Adjusting the Number of Allowed Concurrent HTTP
Connections
It is possible to adjust the resources available for HTTP connections on the VPN-1
gateway. If the traffic volume is greater than 1000 concurrent connections, you can
increase the allowed maximum number of concurrent HTTP connections.
Conversely, if there is a problem installing the security policy due to a lack of
memory, you can decrease the allowed maximum number of concurrent
connections.
From the SmartDashboard main menu, select Policy> Global Properties, and then
SmartDashboard Customization > Configure. In the Advanced Configuration window,
select FireWall-1 > Web Security > Tuning. Adjust the value of the parameter
http_max_concurrent_connections. The default value is 1000.
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Web Intelligence
Backward Compatibility Options for HTTP Protocol
Inspection
Web Intelligence performs high performance kernel-level inspection of all
connections passing through version NG with Application Intelligence (R55W)
gateways or higher.
On earlier version gateways, you have a choice. In Web Intelligence, under HTTP
Protocol Inspection, it is possible to choose whether to perform HTTP protocol
inspection using the kernel for optimized performance, or using the HTTP Security
Server for strict protocol enforcement. The three options are:
•
Configurations apply to all connections: Perform optimized protocol enforcement
The following HTTP protocol inspection options are enforced by the kernel on
all connections (if active): HTTP Format sizes, ASCII Only Request, Header
Rejection, and General HTTP Worm Catcher. Note that in this option, the ASCII
Only Response Headers protection is not performed. If a connection matches a
rule in the Rule Base that activates the Security server, the Security server
performs these options (if activated).
•
Configurations apply to all connections: Perform strict protocol enforcement
The HTTP protocol inspection options are enforced by the Security server.
•
Configurations apply only to connections related to resources used in the Rule Base
For connections related to resources used in the Rule Base, the HTTP protocol
inspection options are enforced by the Security server. For all other connections,
the options are not enforced.
Web Intelligence License Enforcement
A gateway or gateway cluster requires a Web Intelligence license if it enforces one
or more of the following protections:
•
Malicious Code Protector
•
LDAP Injection
•
SQL Injection
•
Command Injection
•
Directory Listing
•
Error Concealment
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Web Intelligence
•
ASCII Only Request
•
Header Rejection
•
HTTP Methods
The actual license required depends on the number of Web servers protected by the
gateway or gateway cluster. The available licenses are shown in Table 7-3.
Table 7-3
Web Intelligence Licenses
Maximum Number
of Web Servers
SKU for Gateways
SKU for Gateway Clusters
3
CPMP-WIT-3-NGX
CPMP-HWIT-3-NGX
10
CPMP-WIT-10-NGX
CPMP-HWIT-10-NGX
Unlimited
CPMP-WIT-U-NGX
CPMP-HWIT-U-NGX
For gateway clusters, a single regular gateway license is required for any one of the
cluster members, and a cluster license for each of the other cluster members.
Licensing is enforced by counting the number of Web servers that are protected by
each Gateway. This number is calculated using the setting in the Protected by field
of the Web Server page of the Web Server object. If *All is specified, the number of
counted Web servers is incremented for all gateways that enforce Web Intelligence
features. If the correct license is not installed, you cannot install a policy on any
gateway.
206
Web Intelligence
Web Intelligence licenses are installed on and attached to a SmartCenter Server,
which allocates licenses to gateways in an optimal way. For example, if three
gateways A, B, and C, protect 3, 7, and 35 Web servers respectively, and the
SmartCenter Server has three licenses: one for 3 Web servers, one for 10 and a
third for an unlimited number. The licenses are allocated as in Table 7-4.
Table 7-4
Example Web Intelligence License Allocation
Gateway
Number of protected
Web Servers
Allocated license
A
3
CPMP-WIT-3-NG
B
7
CPMP-WIT-10-NG
C
35
CPMP-WIT-U-NG
Licenses cannot be accumulated. For example, if a gateway protects six Web
servers, the gateway requires one CPMP-WIT-10-NG license. It is not possible to
use two CPMP-WIT-3-NG licenses.
Understanding HTTP Sessions, Connections and
URLs
To understand how to best use VPN-1 Web security and Web Intelligence
protections, it is important to understand some basic terms and concepts regarding
HTTP sessions, HTTP connections, and URLs.
An HTTP session consists of an HTTP request and an HTTP response. In other
words:
HTTP Session = HTTP Request + HTTP Response
Both the HTTP request and the HTTP response have a header section and a body
section.
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Web Intelligence
HTTP Request Example
Header section
The URL is marked in bold for clarity.
GET
http://www.site.com/path/file.html?param1=val1&param2=value2
HTTP/1.1
Host: www.site.com
Range: 1000-2000
Cookie: cookiename=A172653987651987361BDEF
Body section
<Some content (usually a filled form which will be submitted)>
HTTP Response Example
Header section
HTTP 200 OK
Content-Encoding: gzip
Content-Type: text/html
Transfer-encoding: chunked
Content-Disposition: http://alternative.url.com
Body section
<Some content (usually an HTML page or a binary file)>
HTTP Connections
HTTP/1.1 encourages the transmission of multiple requests over a single TCP
connection. Each request must still be sent in one contiguous message, and a
server must send responses (on a given connection) in the order that it received the
corresponding requests.
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Web Intelligence
The following is an example of an HTTP request connection:
Request # 1
Header section
Post /Hello/ HTTP/1.1
Host: www.walla.co.il
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT5.0)
Pragma: no-cache
Content-length: 20
Connection: Keep-alive
Request #1 Body
This my example body
Request # 2
Header section
Get /scripts/ HTTP/1.1
Host: www.walla.co.il
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT5.0)
Pragma: no-cache
Content-length: 0
Connection: Keep-alive
Understanding URLs
A URL is made up of the Host, Path and Query parameters. In the URL in
Figure 7-7, the Host is http://www.elvis.com, the Path is /alive/qc.html, and the
Query is everything else. VPN-1 and Web Intelligence can filter the URL on these
parameters and decide whether to allow the HTTP request containing a particular
URL.
Figure 7-7 Example URL showing Host, Path and Query components
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Configuring SmartDefense
Configuring SmartDefense
To configure SmartDefense:
1. In the SmartDashboard window, click the SmartDefense tab. The SmartDefense
Settings window opens.
2. In the SmartDefense Settings window, select the SmartDefense category you
want to view information on.
3. To view details of a specific attack, click [+] to expand the branch and then
select the attack.
4. Select the attacks you want to defend against and select Settings to configure
the categories and the specific attacks.
5. Install the security policy. You need to reinstall the security policy in order to
implement changes to the SmartDefense configuration.
Updating SmartDefense with the Latest Defenses
To obtain updates of all the latest defenses from the SmartDefense website:
•
210
Access the SmartDefense Settings > General page, and click Update
SmartDefense.
SmartDefense Services
SmartDefense Services
From the SmartDefense Services tab, you can update all available products from a
central location. The Services tab contains the following three views:
•
Download Updates
•
Advisories
•
Security Best Practices
Download Updates
From the Download Updates tab, you can review information on updates available for
download. Each entry in the table describes the following update packages:
•
VPN-1 Includes SmartDefense and Web Intelligence updates for the following
network objects:
•
VPN-1 Power/UTM gateways
•
VPN-1 Power/UTM clusters
•
VPN-1 UTM Edge or Embedded gateways
•
VPN-1 Power VSX gateways
•
VPN-1 Power VSX clusters
•
InterSpect 1.x and 2.0: Describes SmartDefense and Web Intelligence updates
for centrally managed InterSpect gateways of versions 1.0, 1.1, 1.5 and 2.0.
This entry appears only if the gateways are defined in SmartDashboard.
•
InterSpect NGX: Describes SmartDefense and Web Intelligence updates for
centrally managed InterSpect gateways of version NGX. This entry appears only
if the gateways are defined in SmartDashboard.
•
Connectra 2.0: Describes SmartDefense and Web Intelligence updates for
centrally managed Connectra gateways of version 2.0. This entry appears only if
the gateways are defined in SmartDashboard.
•
Connectra NGX: Describes SmartDefense and Web Intelligence updates for
centrally managed Connectra gateways of version NGX. This entry appears only
if the gateways are defined in SmartDashboard.
•
CI: Describes manual signature updates for gateways that are Anti Virus
installed. To implement this, ensure that Anti Virus is selected in the Check
Point Products list in the General Properties page of the gateway. This entry
appears only if the gateways are defined in SmartDashboard.
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SmartDefense Services
•
VPN-1 UTM Edge CI: Describes manual signature updates for VPN-1 UTM Edge
gateways that are Anti Virus installed, these are defined on the Content Filtering
page of the gateway. This entry appears only if the gateways are defined in
SmartDashboard.
The following Downloads Update table columns provide detailed information on each
update:
1. Last Downloaded Update: Displays the update that is currently downloaded in
SmartCenter. When you click on the link, the highlights of the currently
installed update are displayed. (For the CI entries, such information does not
exist.)
2. Available New Update: Displays the latest available update on the download
center. When you click on the link, the highlights of the newest update are
displayed. (For the CI entries, such information does not exist.)
3. Deployment Status: Shows which updated version is installed for each gateway,
as well as one of the following gateway statuses:
•
Up to date: The gateway has the latest available update installed.
•
Out of date: The gateway does not have the latest update installed.
•
Not available: There is no update currently installed on the gateway.
Advisories
From the Advisories tab, you can view detailed descriptions of SmartDefense
updates and step-by-step instructions on how to activate and configure them.
To view advisories, do one of the following:
212
•
If the administrator is not logged in to the UserCenter, click in the Check Point
Reference column to view a vulnerability description.
•
If the administrator is logged in to the UserCenter (through the Log in to
UserCenter link located at the top of the page), a full step-by-step solution to
the described attacks is provided.
SmartDefense Services
Security Best Practices
From the Security Best Practices tab, you can view Check Point’s latest security
recommendations briefs.
Similar to the Advisories tab, this view also has two states: one when the
administrator is logged in, and the other when the administrator is not logged in
(for additional information, refer to “Advisories” on page 212).
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Configuring SmartDefense Profiles
Configuring SmartDefense Profiles
Creating Profiles
To configure a new profile:
1. Click SmartDefense tab > Profile Management.
2. Click New > Create new profile.
3. Assign a profile name. Click OK.
4. Configure the profile settings by using the SmartDefense navigation tree. Once
a profile is selected, it remains selected when scrolling through the various
SmartDefense protections.
To clone a profile, proceed as follows:
1. Click SmartDefense tab > Profile Management.
2. Select an existing profile.
3. Click New > Clone selected profile. A clone of the selected profile appears in the
profile list. For example, if a profile named Default_Protection is selected and
cloned, the profile named Copy_of_Default_Protection appears in the Profile
Name field.
4. Click OK.
5. Configure the profile settings by using the SmartDefense navigation tree.
Assign a Profile to the Gateway
Assigning a profile to the gateway can be done in two ways:
•
from the gateway itself
•
from the SmartDefense tab
To assign a profile from the gateway itself:
1. Click Manage > Network Objects.
2. Select a gateway and click Edit.
3. Navigate to the SmartDefense page.
4. To disable SmartDefense on this gateway, select Do not apply SmartDefense on
this gateway.
214
Configuring SmartDefense Profiles
To assign a profile, select a profile form the list in the from down menu next to
Assign profile.
5. Click OK.
To assign a profile from the SmartDefense tab:
1. Click SmartDefense tab > Profile Assignment.
2. Select a gateway and click Edit.
3. Navigate to the SmartDefense page.
4. To disable SmartDefense on this gateway, select Do not apply SmartDefense on
this gateway.
To assign a profile, select a profile form the list in the from down menu next to
Assign profile.
5. Click OK.
View Protected Gateways by a Profile
To view a list of gateways that are protected by a specific profile, proceed as
follows:
1. Click SmartDefense tab > Profile Management.
2. Highlight a profile from the list and click Actions > Show Protected Gateways.
The Protected Gateways screen appears with the list of gateways that are
assigned to the selected profile.
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SmartDefense StormCenter Module
SmartDefense StormCenter Module
In This Section
The Need for Cooperation in Intrusion Detection
page 216
Check Point Solution for Storm Center Integration
page 217
Planning Considerations
page 221
Configuring Storm Center Integration
page 222
The Need for Cooperation in Intrusion Detection
The range and sophistication of the techniques used by hackers to penetrate
private networks is ever increasing. However, few organizations are able to maintain
up-to-date protection against the latest attacks. Network Storm Centers are
collaborative initiatives that were set up to help security administrators maintain
the most up-to-date solutions to security threats to their networks. Storm Centers
achieve this by gathering logging information about attacks and sharing it with
other organizations from around the world (Figure 7-8). Storm Centers collate and
present reports on threats to network security in a timely and effective manner.
Figure 7-8 Cooperation Between Organizations and the Network Storm Center
216
SmartDefense StormCenter Module
Check Point Solution for Storm Center Integration
In This Section
Introduction
page 217
How the Block List is Received
page 218
How Logs Are Submitted to the Storm Center
page 219
What a Submitted Log Contains
page 220
Removing Identifying Information from the Submitted Log
page 220
How Authenticity is Assured
page 221
Log Size and Effect on VPN-1 Performance
page 221
Introduction
The SmartDefense Storm Center module is included in the standard VPN-1 product
installation. It enables two-way information flow between the Network Storm
Centers and the organizations requiring network security information.
One of the leading Storm Centers is SANS DShield.org, located at:
http://www.dshield.org/. DShield.org gathers statistics and presents it as a series of
reports at http://www.dshield.org/reports.html.
SmartDefense integrates with the SANS DShield.org Storm Center in the following
two ways (Figure 7-9):
•
The DShield.org Storm Center produces a Block List report, which is a
frequently updated list of address ranges that are recommended for blocking.
The SmartDefense Storm Center module retrieves and adds this list to the
security policy.
•
The Storm Center sends logs to other organizations in order to help them
combat threats that were directed at your network. To send logs, select the
Security Rules and SmartDefense/Web Intelligence protections for which you
want to send logs.
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SmartDefense StormCenter Module
Figure 7-9
How the Block List is Received and Logs are Submitted
How the Block List is Received
The security administrator configures the SmartDefense Block List option by
selecting Network Security > DShield Storm Center > Retrieve and Block Malicious IPs.
Malicious IPs can be blocked for all gateways or for specific gateways.
An agent (daemon) on each VPN-1 gateway for which malicious IP are to be
blocked receives the Block List of malicious IP addresses from
http://secure.dshield.org/block_list_info.html. Following every refresh interval (by
default, three hours), the agent takes the Block List and updates the security policy
with the IP address ranges in the Block List. This process is logged in the
SmartView Tracker, in the VPN-1 log (Figure 7-10).
218
SmartDefense StormCenter Module
Figure 7-10 Retrieval of the Block List in SmartView Tracker
How Logs Are Submitted to the Storm Center
The security administrator decides which types of logs to submit. For example, you
can specify that all Alert or User Defined Alert logs are to be submitted. Logs of
detected attacks (for example, HTTP Worm patterns) can also be submitted.
A log submitting agent (daemon) on the SmartCenter server generates two kinds of
logs: regular logs and a compact log digest, which includes only the number of
Drops and Rejects per port.
The Storm Center informs the log submitting agent whether to send regular logs,
digests, or both kinds of log.
The log submitting agent sends the Storm Center the log types it requested and
those selected by the security administrator using HTTPS POST. The logs are then
compressed into a database.
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SmartDefense 219
SmartDefense StormCenter Module
What a Submitted Log Contains
The logs that are submitted to the Storm Center contain the following information:
•
Connection Parameters: Source IP Address, Destination IP Address, Source
Port, Destination Port (the Service) and IP protocol (for example, UDP, TCP or
ICMP)
•
Rule Base Parameters: Time and action
•
Detailed Log Description
For HTTP Worm patterns, the log contains the same connection and Rule Base
parameters as well as the name of the attack and the detected URL pattern.
The logs are submitted as SmartDefense logs in SmartView Tracker (Figure 7-11).
Figure 7-11 The submission of Logs to the Storm Center in SmartView Tracker
Removing Identifying Information from the Submitted
Log
You can delete identifying information from internal IP addresses in the submitted
log by defining a designated number of bits to mask.
The mask is used to delete as many bits as you want from the internal IP
addresses. A zero bit mask obscures the whole IP address and a 32 bit mask
reveals the whole internal IP address. An 8 bit mask reveals 8 valid bits and
converts the IP address 192.168.46.88 to 0.0.0.88.
220
SmartDefense StormCenter Module
How Authenticity is Assured
The Block List and the submitted logs are securely transferred and authenticated
through SSL. The Certificate of the Storm Center Certificate Authority, which comes
with the Storm Center module, is stored locally and serves the following purposes:
•
To verify the authenticity of the origin of the received Block List.
•
To establish an SSL connection with the Storm Center when submitting logs,
while assuring that the logs are sent only to the Storm Center.
The Certificate Authority of SANS DShield.org is Equifax. equifax.cer is the file
name of the locally stored certificate, which is stored in the conf directory of the
Storm Center module installation.
To send logs to DShield.org, you must first register with them. DShield.org
authenticates log submitters with a username and password that is obtained upon
registration.
Log Size and Effect on VPN-1 Performance
Receiving the Block List does not effect VPN-1 performance because only a very
small amount of data is received. The submitted log is compressed and makes up
a small subset of the complete SmartDefense log. The size of the log depends on
the log interval and the maximum size of the log database (for example,
approximately 10,000 lines of logs take up 200 KB).
Planning Considerations
Which Logs to Send to the Storm Center
Storm Centers are generally interested in receiving logging information on:
•
Unwanted port 80 traffic that reaches the organization.
•
The Drop All rule (the last Rule in the Rule Base), which drops all traffic that
is not explicitly allowed by previous rules.
•
Logs generated by the blocking of malicious IP addresses.
•
SmartDefense and Web Intelligence protections.
Which Logs NOT to Send to the Storm Center
It is not recommended to send logs generated by rules that log internal traffic.
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SmartDefense 221
SmartDefense StormCenter Module
Which Identifying Information to Remove from
Submitted Logs
First decide which of your organization IP addresses that you want to obscure from
the submitted logs. If all your internal addresses are private, nonroutable
addresses, it may not be necessary to mask the addresses. However, you should
keep in mind that even nonroutable addresses can reveal information about your
internal network topology.
Configuring Storm Center Integration
Retrieving and Blocking Malicious IPs
To retrieve and block malicious IPs:
1. In the Security Rule Base, define appropriate rules as necessary. Gateways and
SmartCenter servers must be able to connect to the Storm Center using HTTPS.
2. In SmartDefense, select Network Security > DShield Storm Center > Retrieve and
Block Malicious IPs.
3. Configure the required settings. You can block connections from IP addresses
in the Block List at all gateways or at selected gateways.
Note - Ensure that the Block List is enforced on perimeter gateways ONLY.
4. If you are also submitting logs to DShield and want to report logs generated by
blocking malicious IP addresses, ensure that the Track setting is identical to
the Submit Logs of Type setting in the SmartDefense DShield Storm Center >
Report to DShield section.
5. Install the security policy.
Manually Configuring the Blocking of Malicious IPs
When configured through SmartDefense, the DShield Block List is enforced before
the Rule Base. Because DShield uses statistical analysis and the Block List is
made up of /24 (Class C) networks, not all of those IP addresses are necessarily
malicious. Therefore, in order to prevent reputable IP addresses from being
blocked, you can manually add a Block List rule in the Security Rule Base.
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SmartDefense StormCenter Module
To manually configure blocking malicious IPs:
1. In SmartDefense, select Network Security > DShield Storm Center.
2. Clear the Retrieve and Block Malicious IPs option.
3. Add the Block List rule (Table 7-5) and do the following:
a. Place the Block List rule as high as possible in the Security Rule Base, but
below all authentication rules and any other rules for trusted sources that
should not be blocked.
b. To retrieve and block malicious IPs only at particular gateways, specify
them in the Install On cell of the rule.
Note - Ensure that the Block List is enforced on perimeter gateways ONLY.
c. If you are also submitting logs to DShield and want to report logs generated
by blocking malicious IPs, ensure that the Track setting is identical to the
Submit Logs of Type setting in the SmartDefense DShield Storm Center >
Report to DShield section.
Table 7-5
Source
Destination
Service
Action
Install On
Track
Comment
CPDShield
Any
Any
Drop
Policy
Targets
UserDefine
d
Block List
Rule
4. Install the security policy.
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SmartDefense StormCenter Module
Submitting Logs to DShield.org
To submit logs to DSheild.org:
1. To submit logs to DShield.org, first register at:
http://www.dshield.org/register.html. You receive a DShield username and
password. (You can receive the Block List without registering.)
2. To view DShield reports and statistics about submitted logs, log in to DShield
at: http://www.dshield.org/login.html.
3. VPN-1 gateways and SmartCenter server(s) must be able to connect to the
Storm Center using HTTPS. In the Security Rule Base, define an appropriate
Rule if necessary.
4. In SmartDefense, select Network Security > DShield Storm Center > Report to
DShield.
5. Configure the Submit all logs of type option to determine which logs are sent to
the Storm Center, for example, submit all Alert or User Defined Alert log types.
6. Set the Track option of any rule or SmartDefense/Web Intelligence protection
for the logs that you want to submit.
7. Configure the Hide internal networks using this mask option to prevent the
internal network topology from being exposed by the submitted logs. A 0.0.0.0
mask reveals the whole internal IP address. A 255.255.255.0 mask reveals 8
valid bits and converts the 192.168.46.88 IP address to 0.0.0.88.
8. From the gateway object Topology page, ensure that the topology is correctly
defined for all gateways.
9. Install the security policy.
224
Application Intelligence
Check Point Application Intelligence is a set of advanced capabilities,
integrated into VPN-1 and SmartDefense, which detect and prevent applicationlevel attacks. This section describes how to protect against application-level
attacks for each application protocol, and how to work with anti-virus (CVP) and
URL filtering (UFP) applications.
Chapter
Content Inspection
8
In This Chapter
Anti Virus Protection
page 228
Web Filtering
page 243
227
Anti Virus Protection
Anti Virus Protection
In This Section
Introduction to Integrated Anti Virus Protection
page 228
Architecture
page 229
Configuring Integrated Anti Virus Scanning
page 229
Database Updates
page 230
Understanding Scan By Direction and Scan By IP
page 231
Scanning by Direction: Selecting Data to Scan
page 235
File Type Recognition
page 237
Continuous Download
page 238
Logging and Monitoring
page 239
File Size Limitations and Scanning
page 240
VPN-1 UTM Edge Anti Virus
page 242
Introduction to Integrated Anti Virus Protection
Viruses are a major threat to an network operations and have become increasingly
dangerous and sophisticated. For example, worms, blended threats (which use
combinations of malicious code and vulnerabilities for infection and dissemination)
and trojans.
VPN-1 Content Inspection (CI) gateways contain integrated Anti Virus technology.
Integrated Anti Virus solutions require no extra IT resources and organizations
benefit from their easy management in the familiar Check Point SMART
infrastructure, which includes policy management, logging and monitoring. As a
single box solution, hardware management is also simplified.
Anti Virus protection is available for the HTTP, FTP, SMTP and POP3 protocols. By
default, all protocols are scanned and options for each protocol can be centrally
configured.
228
Anti Virus Protection
Architecture
When Anti Virus scanning is enabled, traffic for the selected protocols is trapped in
the kernel and forwarded to the security server. The security server forwards the
data stream to the Anti Virus engine. The data is allowed or blocked based on the
response of the Anti Virus engine.
Anti Virus scanning is applied only to accepted traffic that has been allowed by the
security policy.
For VPN-1 CI, an Anti Virus configuration makes CVP resource configuration
obsolete. In cases where both Anti Virus and CVP are used ,only Anti Virus works.
Configuring Integrated Anti Virus Scanning
To configure integrated Anti Virus scanning:
1. For all VPN-1 CI gateway objects, select Anti Virus in the Check Point Products
list (Figure 8-1) of the General Properties page.
Figure 8-1 Check Point Products List
2. From the Topology page, define the gateway topology, specifying the internal
networks and the DMZ.
3. Use the Security Rule Base to permit specific services. Anti Virus scanning is
applied only to accepted traffic.
4. In the Content Inspection tab, select the services to be scanned using the
following options:
•
From the Anti Virus page, configure options for file handling and scan
failures.
•
From the Signature Updates page, configure when to perform automatic
signature updates or to initiate a manual signature update.
•
From the SMTP, FTP, HTTP and POP3 pages, configure Anti Virus scanning
options for these services.
Chapter 8
Content Inspection 229
Anti Virus Protection
•
From the File Types page, configure whether to Scan, Block or Pass traffic
according to the file type and configure continuous Download settings.
Database Updates
The following kinds of database updates are available:
•
Automatic: Updates of the virus signature can be scheduled at a predefined
interval.
•
Manual: Updates of virus signatures can be initiated at any time.
When using the CI gateway and/or the SmartCenter server, download updates from
a Check Point server prior to downloading signature updates. First verify that:
•
HTTP and HTTPs Internet connectivity with DNS is properly configured.
•
You have a valid Check Point User Center username and password.
The following signature update methods are available (the default update interval is
120 minutes for all methods):
230
•
Download signature updates every x minutes: Enables you to define the update
interval.
•
Download from Check Point site: Indicates that each VPN-1 gateway is
responsible for contacting Check Point’s site to obtain Anti Virus signatures.
Updates are downloaded directly to the CI gateways. This method usually
results in faster update times.
•
Download from My local SmartCenter Server: Indicates that updates are only
downloaded by the SmartCenter server from the default Check Point signature
distribution server and then redistributed all VPN-1 CI gateways. This method is
useful when Internet access is not available for all gateways or if the download
can only occur once for all the gateways.
Anti Virus Protection
Understanding Scan By Direction and Scan By IP
In This Section
Definitions
page 231
Comparing Scan by Direction and by IP
page 232
Definitions
Scan by Direction and Scan by IP are two file scanning methods used by Content
Inspection. Anti Virus scanning is performed only on traffic that is allowed by the
Security Rule Base.
Scan By Direction
Scan by Direction scans all files passing in one direction, either to or from the
external, internal and/or DMZ networks. Using this method (the default) is fairly
intuitive and does not require the specification of hosts or networks. This method
also enables you to define exceptions, for example, locations to or from which files
are not scanned.
Note - Scan By Direction works only when CI is connected as a gateway and is placed in
line between the external and the internal/DMZ networks. It does not work when VPN-1 CI
is connected as a node in Proxy mode. The gateway topology must also be correctly defined.
Scan By IP Address
Scan by IP address enables you to define which traffic is scanned. For example, if
all incoming traffic from external networks reaches the DMZ using Scan by IP, you
can configure CE to scan only traffic to the FTP, SMTP, HTTP and POP3 servers.
Conversely, Scan by Direction scans all traffic to the DMZ.
When using Scan by IP address, use a Rule Base to specify the source and
destination of the data to be scanned. For FTP, for each rule, you can scan either
the GET or the PUT methods, or both. For HTTP, for each rule, you can scan either
the HTTP Request, the HTTP Response or both.
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Anti Virus Protection
Comparing Scan by Direction and by IP
Scan by Direction enables you to specify file scanning according to the file’s (and
not necessarily the connection’s) origin and destination.
Scan by IP enables you to specify file scanning according to the connection they are
sent through and the protocol phase/command (where applicable).
If you want most or all files in a given direction to be Anti Virus scanned, select
Scan by Direction.
If you want to specify a connection or part of a connection’s source or destination
to be scanned, select Scan by IP.
Comparing Scan by Direction and Scan by IP for SMTP Protocol
For the SMTP protocol, Scan by Direction and Scan by IP are comparable options.
Figure 8-2 illustrates that for the SMTP protocol, the files (data) are always sent in
the same direction as the connection. The SMTP protocol is used to send mail.
Protocols that are used to receive mail (for example, POP3 and IMAP) are not
scanned when SMTP is selected.
Figure 8-2 Comparing Scan by Direction to Scan by IP Address for SMTP
232
Anti Virus Protection
Comparing Scan by Direction and by IP for POP3 Protocol
Figure 8-3 illustrates that for the POP3 protocol, the files (data) are always sent in
the opposite direction of the connection. POP3 is used to retrieve mail.
Figure 8-3 Comparing Scan by Direction to Scan by IP Address for POP3
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Anti Virus Protection
Comparing Scan by Direction and Scan by IP for FTP Protocol
For the FTP protocol, the difference between Scan by IP and Scan by Direction is
illustrated in Figure 8-4. When the FTP GET command is used, files are transferred
in the opposite direction to the connection. When the FTP PUT command is used,
files are transferred in the same direction as the connection. In this scenario, the
Scan by Direction option enables you to scan files without having to consider the
direction of the connection.
Figure 8-4 Comparing Scan by Direction to Scan by IP Address for FTP
234
Anti Virus Protection
Comparing Scan by Direction and Scan by IP for HTTP Protocol
For the HTTP protocol, the difference between Scan by IP and Scan by Direction is
illustrated in Figure 8-5. Using Scan by IP, the source and destination of the
connection are specified and whether the Request, Response or both is scanned.
Figure 8-5 Comparing Scan by Direction to Scan by IP Address for HTTP
Scanning by Direction: Selecting Data to Scan
Using Scan by Direction, you must select the direction of the data to scan, which
depends on whether you want to scan files to or from the internal networks and the
DMZ.
What is a DMZ?
The DMZ (demilitarized zone) is an internal network with an intermediate level of
security. Its security level lies between trusted internal networks, such as a
corporate LAN, and non-trusted external networks, such as the Internet.
Typically, the DMZ contains devices accessible to Internet traffic, for example, Web
(HTTP), FTP, SMTP (email), DNS and POP3 servers.
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Anti Virus Protection
Scan By Direction enables you to define a level of Anti Virus scanning that is
specific to the DMZ. For example, you can decide not to scan traffic passing from
external networks to the DMZ, but to still scan traffic passing from the DMZ to
internal networks and from the external to internal networks.
An internal interface can be defined leading to the DMZ in the VPN-1 CI gateway
topology.
Scan By Direction Options
The following Scan By Direction options are available:
•
Incoming files arriving to (Figure 8-6): Files arriving from external interfaces: the
internal networks (1), the DMZ (2) and the DMZ and internal networks (1 and
2).
Figure 8-6 Scanning Options for Arriving Incoming Files
•
Outgoing files leaving (Figure 7-7): Files leaving through external interfaces: the
internal networks (1), the DMZ (2) and the DMZ and internal networks (1 and
2).
Figure 8-7 Scanning Options for Leaving Outgoing Files
•
236
Internal files (Figure 8-8): If there is no DMZ, files passing between all internal
networks (1). If there is a DMZ, files passing between the DMZ and internal
networks and files passing between all internal networks (between internal
networks (1), from the DMZ to internal networks (2) and from internal networks
to the DMZ (3)).
Anti Virus Protection
Figure 8-8
Scanning Options for Internal Files
File Type Recognition
VPN-1 CI has a built-in File Type recognition engine, which identifies the types of
files passed as part of the connection and enables you to define a per-type policy
for handling files of a given type.
You can specify safe file types that are allowed to pass through the VPN-1 CI
gateway without being scanned for viruses. It is also possible to configure file types
to be scanned or blocked.
The following file types can be be configured:
•
Scan: Performs Anti Virus file scanning according to the settings in the
different services pages. By default, all unrecognized file types are scanned.
•
Block: Does not allow passage of file types that are preset for blocking
according to SmartDefense advisories.
•
Pass: Allows files to pass though the VPN-1 CI gateway without being scanned
for viruses. Files specified as this type are considered to be safe.
File types are considered to be safe if they are not known to contain viruses, for
example, some picture and video files are considered safe. Other formats are
considered to be safe because they are relatively hard to tamper with. What is
considered to be safe changes according to published threats and depends on how
the administrator balances security versus performance considerations.
VPN-1 CI reliably identifies binary file types by examining the file type signatures
(magic numbers). VPN-1 CI does not rely on the file extension (such as *.GIF),
which can be spoofed. It also does not use the MIME headers (such as image/gif)
in HTTP and mail protocols, which can also be spoofed.
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Anti Virus Protection
Continuous Download
The Anti Virus engine acts as a proxy which caches the scanned file before
delivering it to the client for files that need to be scanned.
When scanning large files, if the whole file is scanned before being made available,
the user may experience a long delay before the file is delivered. A similar problem
may arise when using client applications with short timeout periods (for example,
certain FTP clients) to download large files. If the whole file is cached and scanned
before being delivered, the client applications may time out while waiting.
To address this problem, Continuous Download starts sending information to the
client while Anti Virus scanning is still taking place. If a virus is found during the
scan, file delivery to the client is terminated.
You can specify the file types for which you do not want Continuous Download to
occur. Some file types (for example, Adobe Acrobat PDF and Microsoft Power Point
files) can open on a client computer before the whole file has been downloaded. If
Continuous Download is allowed for those file types, and a virus is present in the
opened part of the file, it could infect the client computer.
Note - The SMTP and POP3 protocols support Continuous Download for the entire email
message.
238
Anti Virus Protection
Logging and Monitoring
Logging information on the Anti Virus scan is sent to the SmartCenter server and
can be viewed using SmartView Tracker. Scan results information is shown in the
logs. In addition, there are logs for signature updates, new update checks, and
download results.
The Anti Virus status is monitored using SmartView Monitor. The Anti Virus status
appears under the Firewall-1 product. The status contains information on the
currently installed signature file and the Anti Virus engine version. The Anti Virus
status also includes statistics about scanned files and found viruses.
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Anti Virus Protection
File Size Limitations and Scanning
General Settings
The default settings in the Anti Virus window have been configured to prevent the
Anti Virus engine from overloading. It is recommended that you use the default
settings provided.
If the Anti Virus engine becomes overloaded, use the options in the Anti Virus
window to determine:
•
Whether to allow files that have not been scanned to pass. Selecting this option
leaves you open to virus attacks.
•
Whether to block all files. Selecting this option may result in connectivity
problems.
File Handling
The following file handling options are available:
•
Maximum file size to scan: Limits the file size that is allowed to pass through the
gateway. If the file is a compressed archive, the limit applies to the file after
decompression (the Anti Virus engine decompresses archives before scanning
them). Before performing Anti Virus scanning, the gateway reassembles the
entire file and then scans it. The limit protects the gateway resources and the
destination client.
An archive is a file that contains one or more files in a compressed format.
Archives (and all other file types) are recognized by their binary signature. By
default, any file type that is not identified as non-archive is assumed to be an
archive and the Anti Virus engine tries to expand it.
•
When file exceeds limit: Determines whether to scan or block the file.
Note - An email is treated as an archive and as a result it is not affected when the file
exceeds the limit.
240
Anti Virus Protection
Archive File Handling
The following file handling archiving options are available:
•
Maximum archive nesting level: Limits the number of nested archives (one within
another). This limit protects the gateway and destination client from attacks
that employ deep nesting levels.
•
Maximum compression ratio: Prevents attacks that employ a small size archive
that decompresses into a very large file on target.
•
When archive file exceeds limit or extraction fails: Determines whether to scan or
block the file.
Scan Failure
The following scan failure options are available:
•
When Anti Virus engine is overloaded or scan fails: Determines whether to scan or
block the file.
•
When Anti Virus engine fails to initialize: Determines whether to scan or block the
file.
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Anti Virus Protection
VPN-1 UTM Edge Anti Virus
You can now enable Anti Virus protection within VPN-1 UTM Edge. Selecting the
Anti Virus Protection enabled option indicates that Anti Virus protection is installed
and that updates are sent to the specified gateway.
Using VPN-1 UTM Edge Anti Virus, you can define the maximum archive file sizes
for VPN-1 UTM Edge machines that are scanned, and configure procedures for
when these limits are exceeded and/or the scan fails.
The VPN-1 UTM Edge Anti Virus feature enables you to automatically or manually
update virus signatures for VPN-1 UTM Edge machines and provides you with the
tools to configure how VPN-1 UTM Edge traffic is scanned.
Note - It is important to configure a valid DNS server address on your management and
gateway in order for the signature update to work.
The VPN-1 UTM Edge Anti Virus scanning policy enables you to select the
service(s) to and from which a source and/or destination is scanned. Files set for
scanning is determined using a classic Rule Base, which defines the source and
destination of the connection to be scanned. It is recommended to use this method
if you want to define exactly which traffic to scan, for example, if all incoming
traffic from external networks reaches the DMZ, you can specify that only traffic to
the Anti Virus servers is scanned.
To enable and configure Anti Virus protection:
1. From the General Properties tab of the VPN-1 UTM Edge/Embedded gateway,
select the Anti Virus Protection enabled option.
2. In the Edge Anti Virus section of the Content Inspection tab, configure Anti Virus
to work on VPN-1 UTM Edge gateways. All of the Anti Virus settings in the
Content Inspection tab do not work for VPN-1 UTM Edge machines. The Edge
Anti Virus settings in the Content Inspection tab only work for VPN-1 UTM Edge
machines.
242
Web Filtering
Web Filtering
In This Section
Introduction to Web Filtering
page 243
Terminology
page 244
Architecture
page 244
Configuring Web Filtering
page 245
Introduction to Web Filtering
Access to the Internet can expose your organization to a variety of security threats
and negatively affect employee productivity as a result of non-work-related surfing
and downloading of files.
Due to the problems associated with excessive employee web surfing, organizations
are turning to Web Filtering to control employee Internet access, reduce legal
liability and improve organizational security. Web Filtering enforces filtering rules
based on the organization’s needs and predefined categories made up of URLs and
patterns of URLs.
Web Filtering includes reporting and monitoring tools that capture and present web
traffic data, providing organizations with an in-depth look at how web surfing
affects their organization’s security and supports decisions regarding web surfing
limitations.
A web filter is a function that screens incoming web pages to determine whether or
not to display its web content. The web filter verifies the web page URL against a
list of approved sites and blocks access to complete sites or pages within sites that
contain objectionable material (for example, pornography, illegal software and
spyware).
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Web Filtering
Terminology
The following terms are used in Web Filtering applications:
•
Allow List: A list of allowed URL addresses, for example, a URL in the Allow
List is allowed even if it is associated with a category that is blocked.
•
Block List: A list of blocked URL addresses, for example, a URL in the Block
List is blocked even if it is associated with a category that is not blocked.
•
Blocking Notifications: Contains the message that appears when a URL address
is blocked and the URL to which a blocked URL address is redirected.
•
Category: Contains a group of topics sharing a common attribute (for example,
crime, education and games.
•
Network Exceptions: Contains a list of connections for which Web Filtering
should not be enforced.
•
Web Filter: Enables you to allow or block URLs based on network connections
and/or an external categorized database and local exception lists.
Architecture
When a URL request arrives at a local machine, the machine checks the Network
Exceptions List to determine whether to enforce the Web Filtering policy. The Web
Filtering policy is activated if the connection is accepted by the Security Policy. If
the Web Filtering policy is enforced, the URL header is stripped and the address is
sent to the Web Filter engine.
The URL is allowed or blocked based on categories in the predefined database
and/or the Web Filter Allow/Block Lists. For example, if the URL address matches
two or more categories, and one of them is blocked, the URL address is denied,
however, if the same address appears in the Allow List it is accepted.
The Web Filter engine is installed on VPN-1 and the categories are updated by
selecting: SmartDashboard > Content Inspection > Database Updates > Web Filtering >
Web Filtering Policy.
244
Web Filtering
Configuring Web Filtering
To configure Web Filtering:
1. For all Check Point gateway objects, from the General Properties page, select
Web Filtering in the Check Point Products List to activate Web Filtering for the
specific gateway.
2. In the Content Inspection tab of SmartDashboard, select Web Filtering > Web
Filtering Policy.
3. From the Web Filtering page, configure the following:
a. Select one of the following Web Filtering Policy Modes:
•
On: Web Filtering is active and URLs associated with blocked categories
are blocked.
•
Monitor: URLs associated with blocked categories are logged and not
blocked.
•
Off: Web Filtering is off and does not inspect URL addresses.
b. In the Enforcing Gateways window, select the gateways for which you want to
activate Web Filtering. This window contains all of the gateways for which
Web Filtering can and has been enforced. You can also activate Web
Filtering from the General Properties page by selecting Web Filtering from
the Check Point Products list of the specific gateway.
c. In the Category Selection list, select the URL categories to block.
•
A green icon indicates that URLs associated with this category are
allowed.
•
A red icon indicates that URLs associated with this category are
blocked.
d. In Track Configuration, select how to track a detected URL address. All
options other than None generate a log record in SmartView Tracker.
4. Select Advanced > Allow List to add a URL and/or IP address to be allowed even
if it is associated with a blocked category.
5. Select Advanced > Block List to add a URL and/or IP address to be blocked even
if it is associated with an allowed category.
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Content Inspection 245
Web Filtering
6. In the Advanced area, select Network Exceptions to create a list of the networks
connections through which traffic should not be inspected or in order to enforce
Web Filtering on all web traffic. Network Exceptions works according to a source
and destination Rule Base and does not use the Web Filtering engine.
7. In the Advanced area, select one of the following Blocking Notifications in order
to notify the user when the URL request is blocked:
246
•
Enter the message to be displayed when a URL address is blocked
according to the Web Filtering policy.
•
Enter the URL address to which the user is to be redirected.
9
Chapter
Securing Voice Over IP (VoIP)
In This Chapter
The Need to Secure Voice Over IP
page 248
Introduction to the Check Point Solution for Secure VoIP
page 249
Control Signalling and Media Protocols
page 250
VoIP Handover
page 251
VoIP Application Intelligence
page 253
VoIP Logging
page 257
Securing SIP-Based VoIP
page 259
Troubleshooting SIP
page 278
Securing H.323-Based VoIP
page 279
Securing MGCP-Based VoIP
page 303
Securing SCCP-Based VoIP
page 311
247
The Need to Secure Voice Over IP
The Need to Secure Voice Over IP
Many organizations use Voice over IP (VOIP) connectivity to communicate with
remote locations and to carry data, voice and video. VOIP connectivity is also used
for video conferences and for other activities that provide efficiency and significant
cost savings for an organization.
Voice and video traffic, like any other information on the corporate IP network, has
to be protected as it enters and exits the network. Potential threats from voice and
video traffic include:
248
•
Stealing calls: The caller pretends to be someone else by registering the calls in
the name of another user.
•
Call hijacking: Calls intended for the recipient are redirected to the hijacker.
•
Systems hacking: Hackers abuse ports opened for VoIP connections.
•
Denial of Service attacks: A rogue phone floods the network with calls, thereby
interfering with proper use of the phone network.
Introduction to the Check Point Solution for Secure VoIP
Introduction to the Check Point Solution for
Secure VoIP
VPN-1 secures VoIP traffic in H.323, SIP, MGCP and SCCP environments.
VoIP calls use a series of complex protocols, each of which can carry potentially
threatening information through many ports. Figure 9-1 illustrates the VoIP
protocols supported by VPN-1.
Figure 9-1 Secured VoIP Protocols: SIP, H.323, MGCP and SCCP
VPN-1 ensures that caller and recipient addresses are where they claim to be and
that the caller and recipient are allowed to make and receive VoIP calls. In
addition, VPN-1 examines the contents of the packets passing through every
allowed port to ensure that they contain the correct information. Full stateful
inspection on H.323, SIP, MGCP and SCCP commands ensures that all VoIP
packets are structurally valid, and that they arrive in a valid sequence.
Chapter 9
Securing Voice Over IP (VoIP) 249
Control Signalling and Media Protocols
Control Signalling and Media Protocols
A phone call on both an ordinary digital phone network and a VoIP network is made
up of media and control signals. The voice conversation itself is the media stream.
Dial tones and ringing tones, for example, are an indication that call control
processes are taking place.
The various VoIP protocols all use very different technologies, though they have the
same aims. As illustrated in Figure 9-1 on page 249, VoIP protocols handle the
following call control (or gateway) control and media functions:
•
Call Control (Signalling): Responsible for setting up the call, finding the peer,
negotiating coding protocols, making the connection and ending the call.
•
Gateway Control: Similar to call control, Gateway Control is responsible for
communication between VoIP gateways, rather than between endpoint phones.
These gateways act as intermediaries on behalf of the phones.
•
Media: The actual voice. Both VoIP and ordinary phone networks use RTP/RTCP
for the media. RTP carries the actual media and RTCP carries status and
control information.
Control signals open both fixed (known) and dynamic ports. The parties of a call
then use control signals to negotiate dynamically assigned ports that each side
opens to receive the RTP/RTCP media stream.
250
VoIP Handover
VoIP Handover
The simplest method of communication between VoIP endpoints is to send both the
signalling and media from endpoint to endpoint. In many VoIP networks, however,
the endpoints do not know the location of their peers. In this case, the call is
managed by a handover device, which allows a VoIP call to reach its peer.
When a handover device is used, the signalling follows a different route through the
network than the media. Handover is performed in the following manner:
•
SIP: By the Proxy and/or Registrar.
•
H.323: By the Gatekeeper and/or Gateway.
•
MGCP: By the Call Agent (also called the Media Gateway Controller).
•
SCCP: By the CallManager.
In a regular phone network and in H.323, VPN-1 identifies a user based on the
telephone number or IP address. In other VoIP networks, VPN-1 identifies a user in
other ways, such as by email address or by URL. The phone makes itself known in
the network by registering on an entity that is responsible for mapping each user
identity to an IP address. The endpoints are then able to make calls.
When making a VoIP call, the endpoint making the call first uses control signals to
contact a handover device. This device in turn contacts the destination endpoint,
either directly or through another handover device. After the call setup phase, the
RTP/RTCP media always passes from endpoint to endpoint.
Figure 9-2 illustrates a conversation that VoIP terminal A initiates with VoIP
Terminal B using handover. The handover device manages a group of VoIP phones
(endpoints) including endpoints A and B.
Figure 9-2 VoIP Handover
Chapter 9
Securing Voice Over IP (VoIP) 251
VoIP Handover
The following is a typical VoIP Handover workflow:
1. Endpoint A sends control signals to the handover device.
2. The handover device and the endpoints agree on which ports to use to
communicate, depending on the protocol and the topology.
3. The handover device routes the control signal to endpoint B.
4. The handover device provides A with the IP address and the destination port of
B.
5. A sends the media directly to and from endpoint to endpoint.
When to Enforce Handover
Although enforcing handover using a VoIP domain adds security by providing access
control for the VoIP signal protocols, it is not always possible to define a VoIP
domain. The handover device may be maintained by an external carrier and you do
not know which machines the handover device controls. Likewise, the handover
device may be trusted. In these cases, it is either impossible or unnecessary to
enforce the handover and there is no need to define a VoIP domain.
252
VoIP Application Intelligence
VoIP Application Intelligence
In This Section
Introduction to VoIP Application Intelligence
page 253
Restricting Handover Locations Using a VoIP Domain
page 254
Controlling Signalling and Media Connections
page 255
Protocol-Specific Application Intelligence
page 256
Introduction to VoIP Application Intelligence
VPN-1 secures VoIP networks by eliminating common threats to VoIP traffic. These
threats include call hijacking, call theft, network hacking and Denial of Service
(DoS) attacks (for a description of these threats, refer to “The Need to Secure Voice
Over IP” on page 248).
VPN-1 provides VoIP security by inspecting the VoIP control signals that pass
through the gateway. Using information derived from the control signals, VPN-1 is
responsible for:
•
“Restricting Handover Locations Using a VoIP Domain”
•
“Controlling Signalling and Media Connections”
•
“Preventing Denial of Service Attacks”
•
“Protocol-Specific Application Intelligence”
Chapter 9
Securing Voice Over IP (VoIP) 253
VoIP Application Intelligence
Restricting Handover Locations Using a VoIP
Domain
Handover devices are responsible for rerouting call control signals. VPN-1 prevents
the abuse of the redirection capabilities by defining a VoIP domain. The handover
device can only route calls to the endpoints in its VoIP domain. The VoIP domain
also controls the allowed direction of the call.
For example, in Figure 9-3, if A and B are in the VoIP domain of the handover
device C, VPN-1 ensures that A sends its media streams only to B by verifying that
the address of B (which in step 3 the handover device C provided to A) is in the
VoIP domain. This process prevents unwanted callers from getting through the
firewall.
Figure 9-3 VoIP Security by VPN-1
254
VoIP Application Intelligence
Controlling Signalling and Media Connections
Control signals always pass through the VPN-1 gateway. VPN-1 secures the call by
opening RTP/RTCP ports only for those endpoints that were negotiated during
signalling. It keeps those ports open only for as long as required and then closes
them as soon as the call ends (without waiting for a time-out). The order and
direction of the packets is also secured.
VoIP Billing Issues
VPN-1 closes RTP/RTCP data connections due to potential security threats in VoIP
billing. Security is compromised when the control and media connections follow
different routes. The handover device is responsible for billing, but the RTP (the
voice media) is not routed through this device. Instead, the RTP is routed between
the IP Phones, which poses a security threat because IP Phones can send VoIP
control messages that indicate the call has ended, but continue sending and
receiving media (the RTP connection).
VPN-1 secures billing processes by monitoring the relationship between the control
and media connections. VPN-1 inspects the VoIP services and deletes the media
connection when the messages in the control connection specify that the media
connection must end.
If both endpoints are on the same side of the VPN-1 gateway, the VPN-1 does not
open any ports for the media.
Preventing Denial of Service Attacks
A rogue IP phone could create Denial of Service (DoS) attacks by flooding the
network with calls and interfering with the proper use of the phone network.
SmartDefense protects against DoS attacks directed against VoIP networks by
limiting the number of call attempts per minute that the VPN-1 gateway allows
from an individual IP address. Calls from handover devices are not counted
because they make a large number of calls.
Chapter 9
Securing Voice Over IP (VoIP) 255
VoIP Application Intelligence
Protocol-Specific Application Intelligence
VPN-1 understands complex VoIP protocols and performs application layer filtering
of SIP, H.323, MGCP and SCCP packets. For additional information, refer to:
256
•
“Application Intelligence for SIP” on page 264.
•
“Application Intelligence for H.323” on page 283.
•
“MGCP Network Security and Application Intelligence” on page 305.
•
“SCCP Network Security and Application Intelligence” on page 312
VoIP Logging
VoIP Logging
VPN-1 provides detailed, protocol-specific logs for VoIP traffic. If VoIP logging is
disabled, then only standard logging takes place, showing the source, destination
and protocol information. SIP, H.323, MGCP and SCCP events are logged in
SmartView Tracker. There is also a predefined SmartView Tracker VoIP log query.
To enable VoIP logging:
•
From the Global Properties Log and Alert page, select the Log VoIP connection
option. The following VoIP log fields are displayed:
•
Reg. IP-phones : Call registration events. For SIP and MGCP events, this
field shows the URL, for example, example@checkpoint.com. For H.323
events, this field shows the phone number, for example, 123456#7.
•
Source IP Phone and Destination IP Phone: Call setup events.
•
Media Type: Type of media (audio, video, instant messaging, applications or
unknown) flowing between the source and destination IP Phones.
•
Information: Call and security information, for example, the port used,
commands used and illegal direction and setup messages. For MGCP
events, the commands are shown.
Chapter 9
Securing Voice Over IP (VoIP) 257
Protocol-Specific Security
Protocol-Specific Security
The following sections describe the specific security requirements of the VoIP
protocols supported by VPN-1.
In This Section
258
Securing SIP-Based VoIP
page 259
Securing H.323-Based VoIP
page 279
Securing MGCP-Based VoIP
page 303
Securing SCCP-Based VoIP
page 311
Securing SIP-Based VoIP
Securing SIP-Based VoIP
SIP Architectural Elements in the Security Rule Base
page 260
Supported SIP RFCs and Standards
page 261
Secured SIP Topologies and NAT Support
page 262
Application Intelligence for SIP
page 264
SmartDefense Application Intelligence for SIP
page 265
Synchronizing User Information
page 267
SIP Services
page 267
Using SIP on a Non-Default Port
page 268
ClusterXL and Multicast Support for SIP
page 268
Securing SIP-Based Instant Messenger Applications
page 268
Configuring SIP-Based VoIP
page 269
Note - Before reading this section, read “Introduction to the Check Point Solution for
Secure VoIP” on page 249 to “Protocol-Specific Security” on page 258.
The SIP protocol is described in this section only to the extent required to secure SIP
traffic using VPN-1.
Chapter 9
Securing Voice Over IP (VoIP) 259
Securing SIP-Based VoIP
SIP Architectural Elements in the Security Rule
Base
SIP contains the following VPN-1 supported architectural elements:
•
SIP Terminal(IP Phone): Supports real-time, two-way communication with
another SIP entity. It supports both signalling (SIP commands) and media. In
SIP, only IP enabled phones can be used. IP Phones are defined in
SmartDashboard as a network of IP Phones and there is normally no need to
define network objects for individual IP Phones.
•
Proxy: Manages a number of IP phones. Contacts one or more clients or
next-hop servers and passes the call request through.
•
Redirect Server : Converts SIP URL addresses into zero or more new addresses
and returns them to the client before the VoIP connection begins. It does not
initiate requests or accept calls.
•
Registrar: A server that accepts REGISTER requests. A registrar is typically
co-located with a proxy or redirect server and may offer location services.
The Proxy and the Registrar are handover devices. Handover devices are defined in
SmartDashboard as host nodes that manage a VoIP domain. To limit handover
locations, it is recommended to define a VoIP domain. A VoIP domain is typically a
network or a group of networks. If the handover devices have the same IP address,
only one VoIP domain needs to be defined, otherwise, a VoIP domain must be
defined for each device.
In order to allow SIP conversations, you must create rules that permit SIP control
signals in the VPN-1 gateway. There is no need to define a media rule that
specifies which ports to open and which endpoints that can talk because VPN-1
derives this information from the signalling. Given a particular VoIP signalling rule,
VPN-1 automatically opens ports for the endpoint-to-endpoint RTP/RTCP media
stream.
260
Securing SIP-Based VoIP
Supported SIP RFCs and Standards
The following SIP RFCs and standards are supported by VPN-1:
•
RFC 3261 - The most recent SIP RFC.
•
RFC 3372 - Session Initiation Protocol for Telephones (SIP-T). Refer to
“Configuring SIP-T Support” on page 277 for details.
•
RFC 3311 - UPDATE message.
•
RFC 2976 - INFO message.
•
RFC 3515 - REFER message.
•
RFC 3265 - SIP Events.
•
RFC 3262 - Reliability of Provisional Responses.
•
RFC 3428 - MESSAGE message.
•
MSN messenger over SIP.
•
SIP over TCP.
•
SIP over UDP.
•
SIP early media.
SIP can be configured using the standard, dynamic and nonstandard ports.
Chapter 9
Securing Voice Over IP (VoIP) 261
Securing SIP-Based VoIP
Secured SIP Topologies and NAT Support
Table 9-1 displays a list of VPN-1 supported SIP deployments. You can configure
NAT (either Hide or Static) for the phones in the internal network as well as for the
proxy.
Table 9-1
Supported SIP Topologies
No NAT
NAT for Phones Hide/Static NAT
NAT for Proxy Static NAT
Peer-to-Peer
(Figure 9-4)
Yes
Yes
Not applicable
Proxy in External
(Figure 9-5)
Yes
Yes
Not applicable
The Proxy is any SIP handover device (Proxy and/or Registrar). In Peer-to-Peer
connections topologies both signalling and media pass from endpoint to endpoint.
If there is more than one handover device, signalling passes through one or more
Proxies or Registrars. Once the call has been set up, the media passes peer to peer.
The SmartDashboard configuration depends on the topology (for additional
information, refer to “Configuring SIP-Based VoIP” on page 269).
Figure 9-4 SIP Peer-to-Peer Topology
262
Securing SIP-Based VoIP
Figure 9-5
SIP Proxy in Internet with NAT for Internal Phones
Additional Conditions for Using NAT in SIP Networks
SIP can be used with Network Address Translation (NAT), subject to the following
conditions:
•
Hide NAT can be used for all types of calls (incoming, outgoing, internal and
external). However, Manual Hide NAT rules cannot be used with Hide NAT for
incoming calls. For security reasons, when using Hide NAT for incoming calls,
the Destination of the VoIP call in the appropriate rule in the Security Rule
Base cannot be Any.
•
When both endpoints are on the trusted side of the VPN-1 gateway, calls
cannot be made from the same source to two endpoints, where one endpoint is
NATed (either Static or Hide) and the other is not.
•
Bidirectional NAT of VoIP calls is not supported.
Chapter 9
Securing Voice Over IP (VoIP) 263
Securing SIP-Based VoIP
Application Intelligence for SIP
VPN-1 restricts handover locations and controls signalling and data connections
(for additional information, refer to “VoIP Application Intelligence” on page 253).
For SIP, VPN-1 Application Intelligence ensures that packets conform to RFC 3261
for SIP over UDP and TCP and inspects SIP-based Instant Messaging protocols. It
protects against Denial of Service (DoS) attacks and penetration attempts such as
connection hijacking and manipulation.
VPN-1 validates the expected usage of the SIP protocol, for example, if an end of
call message is sent immediately after the start of the call, the call is denied
because this behavior is characteristic of a DoS attack.
Application layer verification includes:
264
•
Checking for binaries and illegal characters in the packets.
•
Enforcing RFC header fields.
•
Restricting the length of header fields.
•
Removing unknown media types.
Securing SIP-Based VoIP
SmartDefense Application Intelligence for SIP
Additional security verification for SIP connections can be configured in
SmartDefense. There are predefined SIP methods. It is possible to allow or disallow
any command as dictated by the security needs.
To access additional SIP connection security features:
1. In SmartDefense, select Application Intelligence > VoIP > SIP. The following
options are available:
•
Verify SIP header content: Ensures that the headers do not contain forbidden
characters. If found, the message is blocked.
•
Block calls from unregistered users: Prevents unregistered users from making
calls.
•
Block Notify with invalid Subscription state: Blocks Notify messages without a
valid Subscription state header.
•
Block Basic authorization: Blocks SIP messages with the Basic authorization
header.
•
Block the destination from re-inviting calls: Prevents the destination from
opening additional data connections with IP addresses that are not the
same as the first data connection while a call is still active.
•
Maximum invitations per call (from both directions): Defines the maximum
number of participants that can participate in a conference call.
•
Maximum allowed retransmissions: Defines the maximum number of allowed
transmissions.
2. Select SIP Custom Properties. The following options are available:
•
Block SIP early media: Blocks SIP calls that use the early media
mechanism.
•
Block SIP proxy failover: Blocks SIP calls that switch SIP proxies during the
call.
•
Block SIP calls that use two different voice connections (RTP) for incoming
audio and outgoing audio: Applies to SIP implementations that use two
different RTP connections to transfer voice and/or video information
between two peers. If your implementation does not use this scheme, select
this option to ensure that the firewall allows only one of these connections.
Chapter 9
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Securing SIP-Based VoIP
•
Block calls using a proxy or a redirect server: Prevents calls from being made
using an SIP server. When selected, only endpoint-to-endpoint calls are
permitted. The additional security obtained by configuring VoIP domains in
the Security Rule Base is only possible for calls using a proxy or a redirect
server.
•
SIP user suffix length: Defines the user suffix length, for example, the
extension number.
•
Default proxy registration expiration time period: Determines the period of
time the firewall holds registration information from clients in its database
if a timeout is not present in the registration related messages (for
additional information, refer to“Synchronizing User Information” on
page 267). The time period should be greater than or equal to the
registration time period of the client or the proxy. If the client does not
send a user registration message, the registration information is deleted
after the defined time period.
3. Select SIP Filtering. The following options are available:
266
•
Block SIP-based video: Blocks all applications that use SIP to carry video,
which includes the video components of MSN Messenger (when configured
to use SIP). The default is not to block.
•
Block SIP-based audio: Blocks all applications that use SIP to carry audio,
which includes the audio components of MSN Messenger (when configured
to use SIP). The default is not to block.
•
Block SIP-based Instant Messaging: Blocks all applications that use SIP for
instant messaging. The default is to block.
•
To selectively block applications provided by MSN Messenger, select
Instant Messengers > MSN over SIP.
•
To block peer-to-peer applications that allow Instant Messaging, select
Application Intelligence > Peer to Peer.
•
Block Push to talk over cellular: Blocks Nokia’s proprietary Push to talk
messages.
•
Drop unknown SIP messages: Drops SIP messages that the firewall does not
recognize. This option is enabled by default. If disabled, the firewall
accepts unrecognized messages, but only if they conform to the SIP RFC
(i.e., they are properly formatted and contain the mandatory CALL-ID,
FROM and TO fields).
Securing SIP-Based VoIP
Synchronizing User Information
The user IP Phone sends SIP messages to the Redirect server in order to register on
the network. Once a phone is registered, it can make calls.
These SIP messages cross the VPN-1 gateway, which reads them. The VoIP user
databases on VPN-1 and the Redirect server are therefore always synchronized.
Registration makes it possible to initiate calls from outside the VPN-1 gateway to
phones whose addresses are translated using Hide NAT.
If the VPN-1 machine is rebooted, the VoIP user database is deleted. The
cpstop/cpstart commands do not delete the user database.
SIP Services
The following predefined SIP services are available:
•
sip and sip-tcp: Used to enforce handover. Use a VoIP domain in the source or
destination of the rule together with the sip service.
•
sip_any and sip-tcp_any: Used if not enforcing handover. Do not place a VoIP
domain in the source or destination of the rule. Instead, use Any or a network
object, together with the sip_any or sip-tcp_any service. If a VoIP domain is
used with the sip_any or sip-tcp_any service, it is equivalent to the sip service.
For VoIP equipment that uses SIP TCP, use the sip-tcp and sip-tcp_any services.
When it uses UDP, use the sip and sip_any services.
Note - The services sip and sip_any cannot be used in the same rule because they
contradict each other. The same is true for sip-tcp and sip-tcp_any.
When these services are employed, registration messages are tracked and a
database is maintained that includes the details of the IP phones and the users. If
an incoming call is made to a Hide NATed address, VPN-1 verifies that the user
exists in the sip registration database before allowing the call, which can prevent
DoS attacks.
To view a list of the online IP phones:
•
Run the fw tab -t sip_registration -f command.
Chapter 9
Securing Voice Over IP (VoIP) 267
Securing SIP-Based VoIP
Using SIP on a Non-Default Port
By default, SIP uses the UDP port 5060, however, SIP phones and SIP Proxies can
be configured to use a different port. VPN-1 can enforce SIP security on any SIP
port. To configure a new port, a new UDP service must be defined in
SmartDashboard, with SIP rules defined in the Security Rule Base. You can use
both the newly defined service and the predefined services (sip and sip_any) in the
same rule.
To configure a new SIP service:
1. From the SmartDashboard main menu, select Manage > Services > New… >
UDP.
2. In the UDP Service Properties window, name the new service and specify the
new SIP port.
3. Click Advanced….
4. In the Advanced UDP Service Properties window, select the sip_udp Protocol Type
and click OK.
5. Define a rule in the Security Rule Base that uses the new service.
ClusterXL and Multicast Support for SIP
SIP calls can be made across a ClusterXL gateway cluster in either High Availability
or Load Sharing modes. In Load Sharing Mode, the Sticky Decision Function must
be enabled (for additional information, refer to the ClusterXL Administration Guide).
The fw_sip_allow_mcast (true, false) property allows or drops multicast RTP
traffic. The default value of this property is false. This is a per module property. To
change the value, run the fw ctl set int fw_sip_allow_mcast command.
Securing SIP-Based Instant Messenger
Applications
For information on Securing SIP-Based Instant Messenger Applications and MSN
Messenger over SIP, refer to “Securing Instant Messaging Applications” on
page 319.
268
Securing SIP-Based VoIP
Configuring SIP-Based VoIP
In This Section
SIP Rules for a Peer-to-Peer No-Proxy Topology
page 270
SIP Rules for a Proxy in an External Network
page 271
SIP Rules for a Proxy-to-Proxy Topology
page 273
SIP Rules for a Proxy in DMZ Topology
page 275
Configuring SIP-Based Instant Messenger Applications
page 277
Configuring SIP-T Support
page 277
Note - Security rules can be defined that allow either bidirectional calls or only incoming
or outgoing calls. The examples provided in the following sections describe how to define
bidirectional rules.
Chapter 9
Securing Voice Over IP (VoIP) 269
Securing SIP-Based VoIP
SIP Rules for a Peer-to-Peer No-Proxy Topology
Figure 9-6 illustrates SIP rules for a peer-to-peer topology.
Figure 9-6 SIP Peer-to-Peer Topology
To configure SIP rules for a peer-to-peer topology:
1. Define a rule that allows IP phones in Net_A to call Net_Band, and vice versa
(Table 9-2)
Table 9-2
Source
Destination
Service
Action
Comment
Net_A
Net_B
Net_B
Net_A
sip or
sip-tcp
Accept
Bidirectional
calls
2. Define Hide NAT (or Static NAT) for the phones in the internal network by
editing the network object for Net_A.
3. In the NAT tab, select Add Automatic Address Translation Rules and then the
Translation method (Hide or Static).
4. Select Application Intelligence > VoIP > SIP to configure SmartDefense options
(for additional information, refer to “SmartDefense Application Intelligence for
SIP” on page 265 or the online help).
5. Install the security policy.
270
Securing SIP-Based VoIP
SIP Rules for a Proxy in an External Network
Figure 9-7 illustrates a SIP topology with a Proxy in an external network.
Figure 9-7
SIP Proxy in External Network
To enable bidirectional calls between SIP phones in both an internal and an
external network (Net_A and Net_B), and to define NAT for the internal phones:
1. Define the network objects (nodes or networks) for the IP Phones that are
managed by the handover device (SIP Proxy or Registrar), permitted to make
calls and whose calls are tracked by the VPN-1 gateway. In Figure 9-7, these
are Net_A and Net_B.
2. Define the network object for the handover device (SIP_Proxy).
3. Define the VoIP domain object by right-clicking the Network Objects tree and
selecting New… > VoIP Domains > VoIP Domain SIP Proxy. Table 9-3 provides a
list of VoIP domain definitions. If the Proxy and Registrar (SIP_Proxy) are on
one machine with a single IP address, define only one VoIP domain. If they
have different IP addresses, define a VoIP domain for each IP address.
Chapter 9
Securing Voice Over IP (VoIP) 271
Securing SIP-Based VoIP
The definition of the VoIP domain depends on whether or not you want to
enforce handover locations for phones in the external network. For phones in
the internal network, handover should always be enforced.
Table 9-3
VoIP Domain Definition
With Handover
No Handover for
External Phones
Name
VoIP_Domain
VoIP_Domain_A
Related endpoints domain
Group containing
Net_A and Net_B
Net_A
VoIP Gateway installed at
SIP_Proxy
SIP_Proxy
4. Define one of the following SIP rules:
•
For full handover enforcement, define the following rule (Table 9-4):
Table 9-4
Source
Destination
Service
Action
Comment
VoIP_Domain
Net_A
Net_A
VoIP_Domain
sip or
sip-tcp
Accept
Bidirectional calls.
Handover enforced.
•
If you do not want to enforce handover for the external phones (in Net_B),
define the following rules (Table 9-5):
Table 9-5
Source
Destination
Service
Action
Comment
Net_A
Any
sip_any or
sip-tcp_any
Accept
Outgoing calls.
No handover enforced.
Any
VoIP_Domain_A
sip or
sip-tcp
Accept
Incoming calls.
Handover enforced.
For additional information on SIP services, refer to “SIP Services” on
page 267.
5. Define Hide NAT (or Static NAT) for the phones in the internal network by
editing the network object for Net_A. In the NAT tab, select Add Automatic
Address Translation Rules, and then the Translation method (Hide or Static).
6. Select Application Intelligence > VoIP > SIP to configure SmartDefense options
(for additional information, refer to “SmartDefense Application Intelligence for
SIP” on page 265 or the online help.
7. Install the security policy.
272
Securing SIP-Based VoIP
SIP Rules for a Proxy-to-Proxy Topology
Figure 9-8 illustrates a Proxy-to-Proxy topology with Net_A and Net_B on opposite
sides of the VPN-1 gateway.
Figure 9-8 SIP Topology: Proxy-to-Proxy
To enable bidirectional calls between phones in both the internal and the external
networks (Net_A and Net_B) and to define NAT for the internal phones and the
internal Proxy (GW_A):
1. Define the network objects (nodes or networks) for the phones that are
permitted to make calls and whose calls are tracked by the VPN-1 gateway. In
Figure 9-8, these are Net_A and Net_B.
2. Define the network object for the Proxy objects (Proxy_A and Proxy_B).
3. Define Security Rule Base rules with a VoIP domain to enforce handover by
right-clicking the Network Objects tree and selecting New… > VoIP Domains >
VoIP Domain SIP Proxy.
4. Define the following two VoIP domains (Table 9-6):
Table 9-6
Name
VoIP_Domain_A
VoIP_Domain_B
Related endpoints domain
Group containing
Net_A and Net-B
Group containing
Net_A and Net_B
VoIP installed at
Proxy_A
Proxy_B
Chapter 9
Securing Voice Over IP (VoIP) 273
Securing SIP-Based VoIP
5. Define one of the following SIP rules:
•
For full handover enforcement, define the following rule (Table 9-7):
Table 9-7
Source
Destination
Service
Action
Comment
VoIP_Domain_A
VoIP_Domain_B
VoIP_Domain_B
VoIP_Domain_A
sip or
sip-tcp
Accept
Bidirectional calls.
Handover enforced.
•
If you do not want to enforce handover for the external phones (in Net_B),
define the following rules (Table 9-8):
Table 9-8
Source
Destination
Service
Action
Comment
VoIP_Domain_A
Any
sip_any or
sip-tcp_any
Accept
Outgoing calls.
No handover
enforced.
Any
VoIP_Domain_
A
sip or sip-tcp
Accept
Incoming calls.
Handover enforced.
For additional information on SIP services, refer to “SIP Services” on
page 267.
6. Define Hide NAT (or Static NAT) for the phones in the internal network by
editing the network object for the internal network (Net_A). In the NAT tab,
select Add Automatic Address Translation Rules and then the Translation method
(Hide or Static).
7. Define Static NAT for the Proxy in the internal network by repeating step 6 for
the Proxy object (Proxy_A).
8. Select Application Intelligence > VoIP > SIP to configure SmartDefense options
(for additional information, refer to“SmartDefense Application Intelligence for
SIP” on page 265 or the online help.
9. Install the security policy.
274
Securing SIP-Based VoIP
SIP Rules for a Proxy in DMZ Topology
Figure 9-9 illustrates an SIP-based VoIP topology where a Proxy is installed in the
DMZ.
Figure 9-9 SIP Topology: Proxy in the DMZ
To enable bidirectional calls between phones both in an internal and an external
network (Net_A and Net_B) and to define NAT for the internal phones and the
Proxy in the DMZ (Proxy_DMZ):
1. Define the network objects (nodes or networks) for the phones that are
permitted to make calls and whose calls are tracked by the VPN-1 gateway. In
Figure 9-9, these are Net_A and Net_B.
2. Define the network object for the Proxy (Proxy_DMZ).
3. Define Security Rule Base rules with or without a VoIP domain to enforce
handover by right-clicking the Network Objects tree and selecting New… > VoIP
Domains > VoIP Domain SIP Proxy (Table 9-9).
Table 9-9
VoIP Domain Definition
With Handover
Name
VoIP_Domain
Related endpoints domain
Group containing
Net_A and Net_B
VoIP installed at
Proxy_DMZ
Chapter 9
Securing Voice Over IP (VoIP) 275
Securing SIP-Based VoIP
4. Define the rules for full handover enforcement (Table 9-10).
Table 9-10
Source
Destination
Service
Action
Comment
VoIP_Domain
Net_A
Net_B
Net_A
Net_B
VoIP_Domain
sip or
sip-tcp
Accept
Bidirectional calls.
Handover enforced.
For additional information on SIP services, refer to “SIP Services” on
page 267.
5. Define Hide NAT (or Static NAT) for the phones in the internal network by doing
the following:
a. To edit the network object for Net_A, In the NAT tab, select Add Automatic
Address Translation Rules and then the Translation method (Hide or Static).
b. If using Hide NAT, you must select the Hide behind IP address option and
type the IP address of the Hiding address of the phones in the internal
network.
c. If using Hide NAT, you must add a Node object with the Hide NAT IP
address to the Destination of the rule(s) defined in step 4.
6. Define Static NAT for the Proxy in the DMZ by creating a node object for the
Static address of the Proxy (for example, Proxy_DMZ_NATed) and by adding the
following manual NAT rules (Table 9-11):
Table 9-11
Original
Translated
Comment
Source
Destination
Service
Source
Destination
Service
Proxy_DMZ
Net_B
*Any
Proxy_DMZ:
Static
=
=
Outgoing
calls
Net_B
Proxy_DMZ_NATed
*Any
=
Proxy_DMZ:
Static
=
Incoming
calls
7. As for all manual NAT rules, configure proxy-arps. To associate the translated IP
address with the MAC address of the Check Point gateway interface that is on
the same network as the translated addresses, use the arp command in Unix or
the local.arp file in Windows.
The fw ctl arp command displays the ARP proxy table on VPN-1 gateways that
run on Windows. On Unix, use the arp -a command.
276
Securing SIP-Based VoIP
8. Select Application Intelligence > VoIP > SIP to configure SmartDefense options
(for additional information, refer to “SmartDefense Application Intelligence for
SIP” on page 265 or the online help.
9. Install the security policy.
Configuring SIP-Based Instant Messenger Applications
For information on configuring MSN Messenger over SIP, refer to “Configuring
SIP-based Instant Messengers” on page 325.
Configuring SIP-T Support
To configure support for RFC 3372 Session Initiation Protocol for Telephones
(SIP-T):
1. Add the $FWDIR/lib/user.def line on the SmartCenter server:
sipt_hosts = { < first_ip, second_ip> , < first_ip, second_ip> , ....
....,< first_ip, second_ip> } ;
where first_ip and second_ip are the IP addresses between which
(bi-directional) SIP-T are allowed. For example, to allow SIP-T between
192.1.1.1 and 192.1.1.2, and between 192.1.1.1 and 192.1.1.3 add the
following line:
sipt_hosts = { < 192.1.1.1, 192.1.1.2> , < 192.1.1.1, 192.1.1.3> } ;
If the file does not exist, create it.
2. Save the file.
3. Install the security policy.
Chapter 9
Securing Voice Over IP (VoIP) 277
Troubleshooting SIP
Troubleshooting SIP
To view a list of all of the online IP phones that VPN-1 has recorded as having
registered:
Run the fw tab -t sip_registration -f command. The output of this command
is a list in the username; IP address format.
To obtain information on current SIP calls:
Run the fw tab -t sip_state -f command. The following output is displayed:
278
•
Control connection (source, destination).
•
RTP connection (endpoint IP addresses).
•
Call state (established, ended, registration).
•
Media type (audio, video, audio/video, application).
•
Number of reinvites (number of participants in a conference call).
Securing H.323-Based VoIP
Securing H.323-Based VoIP
In This Section
H.323 Architectural Elements in the Security Rule Base
page 279
Supported H.323 RFCs and Standards
page 280
Secured H.323 Topologies and NAT Support
page 280
Application Intelligence for H.323
page 283
SmartDefense Application Intelligence Settings for H.323
page 284
Gatekeeper and Gateway Call Routing
page 284
H.323 Services
page 286
Configuring H.323-Based VoIP
page 287
Note - Before reading this section, read “Introduction to the Check Point Solution for
Secure VoIP” on page 249 to “Protocol-Specific Security” on page 258.
The H.323 protocol is described in this section only to the extent required to secure H.323
traffic using VPN-1.
H.323 Architectural Elements in the Security Rule
Base
VPN-1 supports the following H.323 architectural elements:
•
IP phones, which are IP devices that handle both signalling (that is, the H.323
commands themselves) and media. They connect to an H.323 gatekeeper.
IP Phones are defined in SmartDashboard, usually as a network of IP
Phones. There is normally no need to define network objects for individual
IP Phones.
•
Conventional telephones connect to an H.323 gateway. These are not IP
devices and there is no need to define them in SmartDashboard.
•
A Gatekeeper manages a collection of H.323 devices such as phones. It
converts phone numbers to IP addresses. A Gatekeeper usually provide gateway
services as well.
•
A Gateway provides interoperability between different networks. It translates
between the telephony protocol and IP.
Chapter 9
Securing Voice Over IP (VoIP) 279
Securing H.323-Based VoIP
The Gatekeeper and Gateway are handover devices. Handover devices are defined
in SmartDashboard as host nodes which manage a VoIP domain. In order to limit
handover locations, define a VoIP domain. A VoIP domain is typically a network or
group of networks. If the handover devices have the same IP address, only one VoIP
domain need be defined. If these devices have different IP addresses, a VoIP
domain must be defined for each one.
To allow H.323 conversations, you need only create rules to allow the H.323
control signals through the VPN-1 gateway. There is no need to define a rule for the
media that specifies which ports to open and which endpoints will talk. VPN-1
derives this information from the signalling. Given a particular VoIP signalling rule,
VPN-1 automatically opens ports for the endpoint-to-endpoint RTP/RTCP media
stream.
Supported H.323 RFCs and Standards
•
H.323 Versions 2, 3 and 4. Version 4.
•
H.225 Versions 2, 3 and 4. Version 4.
•
H.245 Versions 3, 5 and 7. Version 7.
Secured H.323 Topologies and NAT Support
VPN-1 supports the H.323 deployments listed in Table 9-12. NAT can be
configured (either Hide or Static) for the phones in the internal network, and
(where applicable) for the Gateway/Gatekeeper.
Table 9-12 Supported H.323 Topologies
Endpoint to Endpoint
(Figure 9-10)
280
No NAT
NAT for Internal
Phones —
Hide/Static NAT
NAT for
Gateway/
Gatekeeper —
Static NAT
Yes
Yes
Not applicable
Securing H.323-Based VoIP
Table 9-12 Supported H.323 Topologies
No NAT
NAT for Internal
Phones—
Hide/Static NAT
NAT for
Gateway/
Gatekeeper —
Static NAT
Gateway/Gatekeeper in External
(Figure 9-11)
Yes
Yes
Not applicable
Gateway/Gatekeeper to
Gateway/Gatekeeper
(Figure 9-12)
Yes
Yes
Yes
Gateway/Gatekeeper in DMZ
(Figure 9-13)
Yes
Yes
Yes
•
Endpoint to Endpoint: The IP Phones communicate directly, without a
Gatekeeper or a Gateway (refer to Figure 9-10). NAT (both hide and static
mode) can be configured for the phones on the internal side of the VPN-1
Gateway. No incoming calls can be made when Hide NAT is configured for the
internal phones.
Figure 9-10 H.323 Topology: Direct Endpoint-to-Endpoint Communication
•
Gatekeeper/Gateway in External Network: The IP Phones use the services of a
Gatekeeper on the external side of the VPN-1 Gateway (refer to Figure 9-11).
This topology enables using the services of a Gatekeeper that is maintained by
another organization. It is possible to configure Hide NAT (or Static NAT or no
NAT) for the phones on the internal side of the VPN-1 gateway.
Chapter 9
Securing Voice Over IP (VoIP) 281
Securing H.323-Based VoIP
Figure 9-11 H.323 Topology: Gatekeeper/Gateway in External Network
•
Gatekeeper/Gateway in the DMZ: The same Gatekeeper/Gateway controls both
endpoint domains. This topology makes it possible to provide
Gatekeeper/Gateway services to other organizations (refer to Figure 9-12).
Static NAT (or no NAT) can be configured for the Gatekeeper/Gateway. Hide
NAT (or Static or no NAT) can be configured for the phones on the internal side
of the VPN-1 gateway.
Figure 9-12 H.323 Topology: Gatekeeper/Gateway in the DMZ
•
282
Gatekeeper/Gateway to Gatekeeper/Gateway : Each Gatekeeper/Gateway controls
a separate endpoint domain (refer to Figure 9-13). Static NAT can be
configured for one of the Gatekeepers/Gateways. For the phones, Hide NAT (or
Static NAT) can be configured for the phones on the internal or the external
side of the VPN-1 gateway (but not both).
Securing H.323-Based VoIP
Figure 9-13 H.323 Topology: Gatekeeper/Gateway to Gatekeeper/Gateway
Application Intelligence for H.323
VPN-1 supports H.323 version 4 and below, which includes H.225 version 4 and
H.245 version 7. It performs the following application layer checks:
•
Strict enforcement of the protocol, including the order and direction of H.323
packets.
•
If the phone number sent is longer than 24 characters, the packet is dropped.
This prevents buffer overruns in the server.
•
Dynamic ports are only opened if the port is not used by another service. For
example: If the Connect message sends port 80 for the H.245, it will not be
opened. This prevents illegal use of well-known ports.
VPN-1 supports Fast Connect, an advanced H.323 capability that ensures that
audio is available as soon as the phone is answered. This feature is active by
default, and is always available.
Chapter 9
Securing Voice Over IP (VoIP) 283
Securing H.323-Based VoIP
SmartDefense Application Intelligence Settings for
H.323
The following additional Application Intelligence checks can be configured via
SmartDefense Application Intelligence > VoIP > H.323:
•
Block connections re-direction: Prevents conversations being handed over on
both sides. It must be unchecked in order to use Gatekeepers or Gateways.
•
Prevent blank source phone numbers for gatekeeper connections: Rejects RAS
connections in which the source phone number is blank. By default, they are
prevented. If a field that should be present in the packet is missing, the packet
is dropped.
•
Disable dynamic T.120: Blocks application-sharing file transfer, used for white
board, chat, and application sharing in applications such as Microsoft
NetMeeting. T.120 is not allowed by default.
•
Block H.245 Tunneling: Prevents the encapsulation a H.245 message in any
Q.931 message. H.245 tunneling conserves resources, synchronizes call
signaling and control, and reduces call setup time. H.245 Tunneling should be
allowed, if the VoIP equipment supports it.
•
Disable dynamic opening of H.323 connections opened from RAS messages:
Controls the way the H323_ras service works. If the service is allowed in the
Rule Base, this setting controls whether control connections required by all
H.323 sessions will be dynamically opened by the firewall. If H.323
connections opened from RAS messages are blocked, it is necessary to allow
the H323 service in the Rule Base. This setting applies only to connections that
start with RAS (that is allowed and inspected by the H323_ras service).
•
Drop H.323 calls that do not start with a SETUP message: Ensures that if this
option is selected, all H.323/Q.931 connections that do not start with a SETUP
message are dropped.
•
T120 timeout: Determines how long a dynamically opened T120 connection can
be idle. After this time, the connection is deleted. The default timeout is 3600
seconds.
Gatekeeper and Gateway Call Routing
H.323 routing modes define which control protocols are allowed to pass between
the Gatekeepers or Gateways, and which are allowed to pass directly between the
endpoints. VPN-1 can be configured to allow one or more routing modes. To
understand routing modes, a basic understanding of H.323 protocols and the
sequence in which they are used is required.
284
Securing H.323-Based VoIP
Signaling and Media Protocols for H.323
The media in H.323 uses the RTP/RTCP and/or T.120 protocols. Signalling is
handled by the following H.323 protocols:
•
RAS manages registration, admission and status. RAS uses a fixed port:
UDP1719.
•
Q.931 manages call setup and termination. Q.931 uses a fixed port: TCP1720.
•
H.245 negotiates channel usage and capabilities. H.245 uses a dynamically
assigned port.
As an H.323 call is processed by a Gatekeeper, these protocols are used in
sequence and then the media passes. To end a call, the signaling protocols are
used in reverse order.
The protocol sequence for a Gateway is the same, except that an endpoint does not
use RAS when it connects to the Gateway.
Routing Modes
H.323 routing modes define which control protocols should pass between the
Gatekeepers or Gateways, and which between the endpoints. VPN-1 can be
configured to allow one or more of the routing modes. At least one of the routing
modes must be selected. If VPN-1 is configured to allow more than one routing
mode, the Gatekeeper/Gateway is free to decide which routing mode to use.
Figure 9-14 illustrates the three routing modes that can be selected.
Figure 9-14 Gatekeeper and Gateway Routing Modes
Chapter 9
Securing Voice Over IP (VoIP) 285
Securing H.323-Based VoIP
The following routing modes are illustrated in Figure 9-14:
•
Direct mode is for Gatekeepers only, and not for Gateways. Only the RAS signals
pass through the Gatekeeper. All other signalling (Q.931 and H.245), as well as
the RTP/RTCP media, passes directly endpoint to endpoint.
•
Call Setup (Q.931) mode allows RAS (used only by Gatekeepers) and Q.931 to
pass through the Gatekeeper/Gateway. H.245 and the RTP/RTCP media pass
endpoint to endpoint.
•
Call Setup (Q.931) and Call Control (H.245) mode allows RAS (for a Gatekeeper
only), Q.931 and H.245 to pass through the Gatekeeper/Gateway. Only the
RTP/RTCP media passes endpoint to endpoint.
H.323 Services
The following predefined services are available for use in H.323 rules. They can be
used to limit the protocols that are permitted during each stage of the H.323 call.
Separate rules can be defined for the different protocols:
Note - The services H323 and H323_any cannot be used in the same rule because they
contradict each other. Similarly, the services H323_ras and H323_ras_any cannot be used
in the same rule.
286
•
H323_ras_only allows only RAS. Cannot be used to make calls. If this service
is used, no Application Intelligence checks (payload inspection or modification)
are made. Do not use in the same rule as the H323_ras service.
•
H323_ras allows a RAS port to be opened, followed by a Q.931 port. Q.931
then opens a H.245 port if needed, which in turn opens ports for RTP/RTCP or
T.120. Use this service to do NAT on RAS messages. Do not use in the same
rule as the H323_ras_only service.
•
H323 allows a Q.931 to be opened (and if needed, a H.245 port,) which in
turn opens ports for RTP/RTCP or T.120. Do not use in the same rule as the
H323_any service.
•
H323_any is like the H323 service, but also allows the Destination in the rule
to be ANY rather than a network object. Only use H323_any if you do not know
the VoIP topology, and are not enforcing handover using a VoIP domain. Do not
use in the same rule as the H323 service.
Securing H.323-Based VoIP
Configuring H.323-Based VoIP
In This Section
Choosing the Type of H.323-VoIP Domain
page 287
H.323 Rule for an Endpoint-to-Endpoint Topology
page 287
H.323 Rules for a Gatekeeper-to-Gatekeeper Topology
page 288
H.323 Rules for a Gateway-to-Gateway Topology
page 291
H.323 Rules for a Gatekeeper in the External Network
page 292
H.323 Rules for a Gateway in the External Network
page 295
H.323 Rules for a Gatekeeper in DMZ Topology
page 296
H.323 Rules for a Gateway in DMZ Topology
page 300
Choosing the Type of H.323-VoIP Domain
Configure a VoIP domain for H.323 phones if they use the Gateway or Gatekeeper
to make calls. Select either a Gateway or Gatekeeper object according to the
following criteria:
•
Use a VoIP Domain H.323 Gateway if the first packet that the device sees when
a call is initiated is a Q.931/H.225 packet, and not an RAS packet.
•
Use a VoIP Domain H.323 Gatekeeper if the first packet that the device sees
when a call is initiated is an RAS/H.225 packet.
For an H.323 Gatekeeper, the VoIP domain corresponds to the zone of that
Gatekeeper. A zone is a collection of terminals that are managed by a single
Gatekeeper. A zone has one and only one Gatekeeper.
If the Gatekeeper and Gateway have different IP addresses, define a VoIP domain
for each one. If the Gateway and Gatekeeper are on single machine, and have the
same IP address, define only a single VoIP Domain H.323 Gatekeeper object.
H.323 Rule for an Endpoint-to-Endpoint Topology
An endpoint-to-endpoint topology is shown in Figure 9-15, with Net_A and Net_B
on opposite sides of the VPN-1 gateway. The following procedure explains how to
allow bidirectional calls between the phones in the internal network (Net_A) and
phones in an external network (Net_B), and how to define NAT for the internal
phones. No incoming calls can be made when Hide NAT is configured for the
internal phones.
Chapter 9
Securing Voice Over IP (VoIP) 287
Securing H.323-Based VoIP
Figure 9-15 H.323 Topology: Direct Endpoint-to-Endpoint Communication
To define an H.323 rule for endpoint-to-endpoint topology:
1. Define the following rule:
Table 9-13
Source
Destination
Service
Action
Net_A
Net_B
Net_B
Net_A
H323
Accept
2. To define Hide NAT (or Static NAT) for the phones in the internal network, edit
the network object for the internal network (Net_A). In the NAT tab, check Add
Automatic Address Translation Rules, and select the Translation method (Hide or
Static).
3. Configure the SmartDefense options under Application Intelligence > VoIP >
H.323 as required. For details, refer to “SmartDefense Application Intelligence
Settings for H.323” on page 284, or the online help.
4. Install the security policy.
H.323 Rules for a Gatekeeper-to-Gatekeeper Topology
A Gatekeeper-to-Gatekeeper topology is shown in Figure 9-16, with Net_A and
Net_B on opposite sides of the VPN-1 gateway. The following procedure explains
how to allow bidirectional calls between the phones in the internal network (Net_A)
and phones in an external network (Net_B), and how to define NAT for the internal
phones and the internal Gatekeeper (GK_A).
288
Securing H.323-Based VoIP
Figure 9-16 H.323 Topology: Gatekeeper-to-Gatekeeper
To define an H.323 rule for gatekeeper-to-gatekeeper topology:
1. Define the network objects (Nodes or Networks) for the phones which use the
Gatekeeper for registration, and are allowed to make calls, and whose calls are
tracked by the VPN-1 gateway.
In the example in Figure 9-16, these are Net_A and Net_B.
2. Define the Network object for the Gatekeeper objects (GK_A and GK_B)
3. Define Security Rule Base rules either with or without a VoIP domain.
To enforce handover, define VoIP domains. Right-click the Network Objects
tree, and select New… > VoIP Domains > VoIP Domain H.323 Gatekeeper. Define
two VoIP domains, as follows:
Table 9-14
Name
VoIP_Domain_A
VoIP_Domain_B
Related endpoints domain
Group containing
Net_A
Group containing
Net_B
VoIP installed at
GK_A
GK_B
4. In the Routing Mode tab, define permitted routing modes for the Gatekeepers.
For an explanation of the modes, refer to “Routing Modes” on page 285. It is
important to select at least one option.
Chapter 9
Securing Voice Over IP (VoIP) 289
Securing H.323-Based VoIP
5. Now define the rules. To enforce handover, define the following rule with VoIP
domains:
Table 9-15
Source
Destination
Service
Action
Comment
VoIP_Domain_A
VoIP_Domain_B
VoIP_Domain_B
VoIP_Domain_A
H323_ras
Accept
Bidirectional calls.
Handover
enforced.
If you do not want to enforce handover, define the following rules:
Table 9-16
Source
Destination
Service
Action
Comment
GK_A
GK_B
H323_ras_only
Accept
No handover.
Net_A
Net_B
Net_A
Net_B
H323
Accept
No handover.
When rules without a VoIP domain are defined, all connections other than
H323_ras must be peer to peer.
For an explanation of the H.323 services, refer to “H.323 Services” on
page 286.
6. To define Hide NAT (or Static NAT) for the phones in the internal network, edit
the network object for the internal network (Net_A). In the NAT tab, select Add
Automatic Address Translation Rules, and select the Translation method (Hide or
Static).
7. To define Static NAT for the Gatekeeper/Gateway in the internal network, repeat
step 6 for the Gatekeeper object (GK_A).
8. It is recommended to make the time-out of the H323_ras service equal to or
greater than the Gatekeeper registration time-out. Configure the time-outs in
the Advanced Properties window of the Service object.
9. Configure the SmartDefense options under Application Intelligence > VoIP >
H.323 as required. For details, refer to “SmartDefense Application Intelligence
Settings for H.323” on page 284, or the online help.
10. Install the security policy.
290
Securing H.323-Based VoIP
H.323 Rules for a Gateway-to-Gateway Topology
A Gateway-to-Gateway topology is shown in Figure 9-17, with Net_A and Net_B on
opposite sides of the VPN-1 gateway. The following procedure explains how to allow
bidirectional calls between the phones in the internal network (Net_A), and phones
in an external network (Net_B), and how to define NAT for the internal phones and
the internal gateway (GW_A).
Figure 9-17 H.323 Topology: Gateway-to-Gateway
To define an H.323 rule for gateway-to-gateway topology:
1. Define the network objects (Nodes or Networks) for the phones which are
allowed to make calls, and whose calls are tracked by the VPN-1 Gateway.
For the example in Figure 9-17, these are Net_A and Net_B.
2. Define the network object for the gateway objects (GW_A and GW_B)
3. Define Security Rule Base rules with a VoIP domain to enforce handover.
Right-click the Network Objects tree, and select New… > VoIP Domains > VoIP
Domain H.323 Gateway.
4. Define two VoIP domains, as follows:
Table 9-17
Name
VoIP_Domain_A
VoIP_Domain_B
Related endpoints domain
Group containing
Net_A
Group containing
Net_B
VoIP installed at
GW_A
GW_B
5. In the Routing Mode tab, define permitted routing modes for the Gateways. For
an explanation of the modes, refer to “Routing Modes” on page 285. It is
important to select at least one option.
Chapter 9
Securing Voice Over IP (VoIP) 291
Securing H.323-Based VoIP
6. Now define the rules. To enforce handover, define the following rule with VoIP
domains:
Table 9-18
Source
Destination
Service
Action
Comment
VoIP_Domain_A
VoIP_Domain_B
VoIP_Domain_B
VoIP_Domain_A
H323
Accept
Bidirectional calls.
Handover enforced.
For an explanation of the H.323 services, refer to “H.323 Services” on
page 286.
7. To define Hide NAT (or Static NAT) for the phones in the internal network, edit
the network object for the internal network (Net_A). In the NAT tab, select Add
Automatic Address Translation Rules, and select the Translation method (Hide or
Static)
8. To define Static NAT for the Gatekeeper/Gateway in the internal network, repeat
step 6 for the Gatekeeper/Gateway object (GK_A).
9. Configure the SmartDefense options under Application Intelligence > VoIP >
H.323 as required. For details, refer to “SmartDefense Application Intelligence
Settings for H.323” on page 284, or the online help.
10. Install the security policy.
H.323 Rules for a Gatekeeper in the External Network
An H.323 topology with a Gatekeeper in the Internet is shown in Figure 9-18, with
Net_A and Net_B on opposite sides of the VPN-1 gateway. The following procedure
explains how to allow bidirectional calls between the phones in the internal network
(Net_A) and phones in an external network (Net_B), and how to define NAT for the
internal phones.
292
Securing H.323-Based VoIP
Figure 9-18 H.323 Topology: Gatekeeper In External Network
To define an H.323 rule for a gatekeeper in the external network:
1. Define the network objects (Nodes or Networks) for the phones which use the
Gatekeeper for registration, and that are allowed to make calls, and whose calls
are tracked by the VPN-1 Gateway.
For the example in Figure 9-18, these are Net_A and Net_B.
2. Define the network object for the Gatekeeper (GK_B)
3. Define Security Rule Base rules either with or without a VoIP domain.
To enforce handover, define a VoIP domain. Right-click the Network Objects
tree, and select New… > VoIP Domains > VoIP Domain H.323 Gatekeeper.
4. Define a VoIP domain, as follows:
Table 9-19
Name
VoIP_Domain
Related endpoints domain
Group containing
Net_A and Net_B
VoIP installed at
GK_A
5. In the Routing Mode tab, define permitted routing modes for the Gatekeeper. For
an explanation of the modes, refer to “Routing Modes” on page 285. It is
important to select at least one option.
Chapter 9
Securing Voice Over IP (VoIP) 293
Securing H.323-Based VoIP
6. Now define the rules. To enforce handover, define the following rule with a VoIP
domain:
Table 9-20
Source
Destination
Service
Action
Comment
Net_A
Net_B
VoIP_Domain
VoIP_Domain
Net_A
H323_ras
H323
Accept
Bidirectional calls.
Handover enforced.
If you do not want to enforce handover, define the following rules:
Table 9-21
Source
Destination
Service
Action
Comment
Net_A
GK_B
H323_ras_only
Accept
No handover.
Net_A
Net_B
Net_A
Net_B
H323
Accept
No handover.
When rules without a VoIP domain are defined, all connections other than RAS
connections must be peer to peer.
For an explanation of the H.323 services, refer to “H.323 Services” on
page 286.
7. To define Hide NAT (or Static NAT) for the phones in the internal network:
•
Edit the network object for the internal network (Net_A). In the NAT tab,
check Add Automatic Address Translation Rules, and select the Translation
method (Hide or Static)
•
If defining Hide NAT, add a Node object with the Hide NAT IP address to
the Destination of the rule(s) defined in step 6.
8. It is recommended to make the time-out of the H323_ras service greater or
equal to the Gatekeeper registration time-out. Configure the time-outs in the
Advanced Properties window of the Service object.
9. Configure the SmartDefense options under Application Intelligence > VoIP >
H.323 as required. For details, refer to “SmartDefense Application Intelligence
Settings for H.323” on page 284, or the online help.
10. Install the security policy.
294
Securing H.323-Based VoIP
H.323 Rules for a Gateway in the External Network
An H.323 topology with a Gateway in the Internet is shown in Figure 9-19, with
Net_A and Net_B on opposite sides of the VPN-1 gateway. The following procedure
explains how to allow bidirectional calls between the phones in the internal network
(Net_A) and phones in an external network (Net_B), and how to define NAT for the
internal phones.
Figure 9-19 H.323 Topology: Gateway In External Network
To define an H.323 rule for a gateway in the external network:
1. Define the network objects (Nodes or Networks) for the phones that are allowed
to make calls, and whose calls are tracked by the VPN-1 gateway.
For the example in Figure 9-19, these are Net_A and Net_B.
2. Define the network object for the Gateway (GW_B)
3. Define Security Rule Base rules with a VoIP domain to enforce handover.
Right-click the Network Objects tree, and select New… > VoIP Domains > VoIP
Domain H.323 Gateway. Define a VoIP domain, as follows:
Table 9-22
Name
VoIP_Domain
Related endpoints domain
Group containing
Net_A and Net_B
VoIP installed at
GW_A
4. In the Routing Mode tab, define permitted routing modes for the Gateway. For
an explanation of the modes, refer to “Routing Modes” on page 285. It is
important to select at least one option.
Chapter 9
Securing Voice Over IP (VoIP) 295
Securing H.323-Based VoIP
5. Now define the rules. To enforce handover, define the following rule with a VoIP
domain:
Table 9-23
Source
Destination
Service
Action
Comment
Net_A
Net_B
VoIP_Domain
VoIP_Domain
Net_A
H323
Accept
Bidirectional calls.
Handover enforced.
For an explanation of the H.323 services, refer to “H.323 Services” on
page 286.
6. To define Hide NAT (or Static NAT) for the phones in the internal network:
•
Edit the network object for the internal network (Net_A). In the NAT tab,
select Add Automatic Address Translation Rules, and select the Translation
method (Hide or Static).
•
If using Hide NAT, you must add a Node object with the Hide NAT IP
address to the Destination of the rule(s) defined in step 5.
7. Configure the SmartDefense options under Application Intelligence > VoIP >
H.323 as required. For details, refer to “SmartDefense Application Intelligence
Settings for H.323” on page 284, or the online help.
8. Install the security policy.
H.323 Rules for a Gatekeeper in DMZ Topology
A H.323-based VoIP topology where a Gatekeeper is installed in the DMZ is shown
in Figure 9-20. The following procedure explains how to allow bidirectional calls
between the phones in the internal network (Net_A) and phones in an external
network (Net_B), and how to define NAT for the internal phones and the
Gatekeeper in the DMZ (GK_DMZ).
296
Securing H.323-Based VoIP
Figure 9-20 H.323 Topology: Gatekeeper in the DMZ
To define an H.323 rule for a gatekeeper in the DMZ:
1. Define the network objects (Nodes or Networks) for the phones which use the
Gatekeeper for registration, and that are allowed to make calls, and whose calls
are tracked by the VPN-1 Gateway.
For the example in Figure 9-20, these are Net_A and Net_B.
2. Define the network object for the Gatekeeper (GK_DMZ).
3. Define Security Rule Base rules either with or without a VoIP domain.
To enforce handover, define VoIP domains. Right-click the Network Objects
tree, and select New… > VoIP Domains > VoIP Domain H.323 Gatekeeper.
The definition of the VoIP domain depends on whether or not you want to
enforce handover locations for phones in the external network. For phones in
the internal network, handover should always be enforced.
Table 9-24
VoIP Domain Definition
With Handover
No Handover for
External Phones
Name
VoIP_Domain
VoIP_Domain_A
Related endpoints domain
Group containing
Net_A and Net_B
Net_A
VoIP installed at
GK_DMZ
GK_DMZ
4. In the Routing Mode tab, define permitted routing modes for the Gatekeeper. For
an explanation of the modes, refer to “Routing Modes” on page 285. It is
important to select at least one option.
Chapter 9
Securing Voice Over IP (VoIP) 297
Securing H.323-Based VoIP
5. Now define the rules. For full handover enforcement, define the following rule:
Table 9-25
Source
Destination
Service
Action
Comment
VoIP_Domain
Net_A
Net_B
Net_A
Net_B
VoIP_Domain
H323_ras
Accep
t
Bidirectional calls.
Handover enforced.
If you do not want to enforce handover for the external phones (in Net_B),
define the following rules:
Table 9-26
Source
Destination
Service
Action
Comment
Net_A,
Net_B,
GK_DMZ
Net_A,
Net_B,
GK_DMZ
H323_ras_only
Accept
Outgoing calls.
No handover enforced.
Net_A
Net_B
Net_A
Net_B
H323
Accept
No Handover enforced.
When rules without a VoIP domain are defined, all connections other than
H323_ras are only allowed to be peer to peer.
For an explanation of the H.323 services, refer to “H.323 Services” on
page 286.
6. To define Hide NAT (or Static NAT) for the phones in the internal network:
•
Edit the network object for Net_A. In the NAT tab, select Add Automatic
Address Translation Rules, and select the Translation method (Hide or Static).
•
If using Hide NAT, you must select the Hide behind IP address option, and
type the IP address of the Hiding address of the phones in the internal
network.
•
If using Hide NAT, you must add a Node object with the Hide NAT IP
address to the Destination of the rule(s) defined in step 5.
7. To define Static NAT for the Gatekeeper in the DMZ, add manual NAT rules, as
follows:
•
298
Create a Node object for the Static address of the Gatekeeper (for example:
GK_DMZ_NATed).
Securing H.323-Based VoIP
•
Define the following manual NAT rules:
Table 9-27
Original
Translated
Comment
Source
Destination
Service
Source
Destination
Service
GK_DMZ
Net_B
*Any
GK_DMZ:
Static
=
=
Outgoing
calls
Net_B
GK_DMZ_N
ATed
*Any
=
GK_DMZ:
Static
=
Incoming
calls
•
As for all manual NAT rules, configure proxy-ARPs. In other words, you
must associate the translated IP address with the MAC address of the
Check Point Gateway interface that is on the same network as the
translated addresses. Use the arp command in Unix or the local.arp file in
Windows.
The command fw ctl arp displays the ARP proxy table on VPN-1 Gateways
that run on Windows. On Unix, use the arp -a command.
8. It is recommended to make the time-out of the H.323_ras service greater than
or equal to the Gatekeeper registration time-out. Configure the time-outs in the
Advanced Properties window of the Service object.
9. Configure the SmartDefense options under Application Intelligence > VoIP >
H.323 as required. For details, refer to “SmartDefense Application Intelligence
Settings for H.323” on page 284, or the online help.
10. Install the security policy.
Chapter 9
Securing Voice Over IP (VoIP) 299
Securing H.323-Based VoIP
H.323 Rules for a Gateway in DMZ Topology
A H.323-based VoIP topology where a Gateway is installed in the DMZ is shown in
Figure 9-21. The following procedure explains how to allow bidirectional calls
between the phones in the internal network (Net_A) and phones in an external
network (Net_B), and how to define NAT for the internal phones and the Gateway in
the DMZ (GK_DMZ).
Figure 9-21 H.323 Topology: Gateway in the DMZ
To define an H.323 rule for a gateway in the DMZ:
1. Define the network objects (Nodes or Networks) for the phones that are allowed
to make calls, and whose calls are tracked by the VPN-1 Gateway.
For the example in Figure 9-21, these are Net_A and Net_B.
2. Define the network object for the Gateway (GW_DMZ).
3. Define Security Rule Base rules with or without a VoIP domain to enforce
handover. Right-click the Network Objects tree, and select New… > VoIP
Domains > VoIP Domain H.323 Gateway.
Table 9-28
VoIP Domain Definition
With Handover
Name
VoIP_Domain
Related endpoints domain
Group containing
Net_A and Net_B
VoIP installed at
GK_DMZ
4. In the Routing Mode tab, define permitted routing modes for the Gateway. For
an explanation of the modes, refer to “Routing Modes” on page 285. It is
important to select at least one option.
300
Securing H.323-Based VoIP
5. Now define the rules for full handover enforcement:
Table 9-29
Source
Destination
Service
Action
Comment
VoIP_Domain
Net_A
Net_B
Net_A
Net_B
VoIP_Domain
H323
Accept
Bidirectional calls.
Handover enforced.
For an explanation of the H.323 services, refer to “H.323 Services” on
page 286.
6. To define Hide NAT (or Static NAT) for the phones in the internal network:
•
Edit the network object for Net_A. In the NAT tab, check Add Automatic
Address Translation Rules, and select the Translation method (Hide or Static).
•
If using Hide NAT, you must select the Hide behind IP address option, and
type the IP address of the Hiding address of the phones in the internal
network.
•
If using Hide NAT, you must add a Node object with the Hide NAT IP
address to the Destination of the rule(s) defined in step 5.
Chapter 9
Securing Voice Over IP (VoIP) 301
Securing H.323-Based VoIP
7. To define Static NAT for the Gateway in the DMZ, add manual NAT rules, as
follows:
•
Create a Node object for the Static address of the Gateway (for example:
GW_DMZ_NATed).
•
Define the following manual NAT rules:
Table 9-30
Original
Translated
Comment
Source
Destination
Service
Source
Destination
Service
GW_DMZ
Net_B
*Any
GW_DMZ:
Static
=
=
Outgoing
calls
Net_B
GW_DMZ_NATed
*Any
=
GW_DMZ:
Static
=
Incoming
calls
•
As for all manual NAT rules, configure proxy-arps. In other words, you must
associate the translated IP address with the MAC address of the Check
Point Gateway interface that is on the same network as the translated
addresses. Use the arp command in Unix or the local.arp file in Windows.
The command fw ctl arp displays the ARP proxy table on VPN-1 Gateways
that run on Windows. On Unix, use the arp -a command.
8. Configure the SmartDefense options under Application Intelligence > VoIP >
H.323 as required. For details, refer to “SmartDefense Application Intelligence
Settings for H.323” on page 284, or the online help.
9. Install the security policy.
302
Securing MGCP-Based VoIP
Securing MGCP-Based VoIP
The Need for MGCP
page 303
MGCP Protocol and Devices
page 304
MGCP Network Security and Application Intelligence
page 305
Secured MGCP Topologies and NAT Support
page 307
Synchronizing User Information
page 308
Configuring MGCP-Based VoIP
page 309
Note - Before reading this section, read “Introduction to the Check Point Solution for
Secure VoIP” on page 249 to “Protocol-Specific Security” on page 258.
The MGCP protocol is described in this section only to the extent required to secure MGCP
traffic using VPN-1.
The Need for MGCP
Regular phones are relatively inexpensive because they do not need to be complex;
they are fixed to a specific switch at a central switching location. IP phones and
devices, on the other hand, are not fixed to a specific switch, so they must contain
processors that enable them to function and be intelligent on their own,
independent from a central switching location. This makes the terminal (phone or
device) more complex and, therefore, more expensive.
The MGCP (Media Gateway Control Protocol) protocol is meant to simplify
standards for VoIP by eliminating the need for complex, processor-intense IP
telephony devices, thus simplifying and lowering the cost of these terminals.
MGCP interoperates with SIP and H.323, but does not replace them. MGCP
converts audio signals carried on telephone circuits (PSTN) to data packets carried
over the Internet or other packet networks.
Chapter 9
Securing Voice Over IP (VoIP) 303
Securing MGCP-Based VoIP
MGCP Protocol and Devices
MGCP is a protocol for controlling telephony gateways from external call control
devices called Call Agents (also known as Media Gateway Controllers).
MGCP is a master/slave protocol, which means it assumes limited intelligence at
the edge (endpoints) and intelligence at the core (Call Agent). In this it differs from
SIP and H.323, which are peer-to-peer protocols.
The MGCP assumes that the call control devices, or Call Agents, will synchronize
with each other to send commands to devices under their control called Media
Gateways. Call Agents can also connect directly to IP Phones. The Media Gateways
or IP Phones are expected to execute commands sent by the Call Agents.
Figure 9-22 shows the MGCP elements and a simplified call control process.
Figure 9-22 MGCP Elements
The Call Agent and Media Gateways are defined in SmartDashboard, usually as
Node objects.
To allow MGCP conversations you need only create rules to allow the MGCP control
signals through the VPN-1 gateway. There is no need to define a rule for the media
that specifies which ports to open and which endpoints will talk. VPN-1 derives this
information from the signalling. Given a particular VoIP signalling rule, VPN-1
automatically opens ports for the endpoint-to-endpoint RTP/RTCP media stream.
304
Securing MGCP-Based VoIP
Call Agent or Media Gateway Controller
A Call Agent is a network device that:
•
Provides call signaling, control and processing intelligence to the media
gateway.
•
Sends and receives commands to/from the media gateway.
Media Gateway
A Media Gateway is a network device that:
•
Provides conversion between the audio signals carried on telephone circuits and
data packets carried over the Internet or over other packet networks.
•
Sends notification to the call agent about endpoint events.
•
Executes commands from the call agents.
Media Gateways normally support features such as conference calls, 3-way
brokering and supervisor inspection. All of these features are supported by the
predefined VPN-1 MGCP services (MGCP-CA and MGCP-MG).
MGCP IP Phones
An MGCP IP Phone is a network device that:
•
Provides conversion between the audio signals carried over the Internet or over
other packet networks.
•
Sends notification to the call agent about its events.
•
Executes commands from the call agents.
MCGP IP Phones normally support features such as conference calls, three-way
brokering, and supervisor inspection. All of these features are supported by the
predefined VPN-1 MGCP services (MGCP-CA and MGCP-MG).
MGCP Network Security and Application
Intelligence
VPN-1 provides full network level security for MGCP. VPN-1 enforces strict
compliance with RFC-2705, RFC-3435 (version 1.0), and ITU TGCP specification
J.171. In addition, all VPN-1 capabilities are supported, such as inspection of
fragmented packets, anti-spoofing, and protection against DoS attacks.
Chapter 9
Securing Voice Over IP (VoIP) 305
Securing MGCP-Based VoIP
VPN-1 restricts handover locations and controls signalling and data connections, as
described in “VoIP Application Intelligence” on page 253.
SmartDefense can perform additional content security checks for MGCP
connections, thereby providing a greater level of protection. MGCP-specific
Application Intelligence security is configured via SmartDefense, under Application
Intelligence > VoIP > MGCP. Three options are available:
•
Blocked/Accepted Commands
•
Verify MGCP Header Content
•
Allow Multicast RTP Connections
Blocked/Accepted Commands
There are nine predefined MGCP commands. Some commands are made by the
Call Agent, and others by the Gateway, as shown in Table 9-31. It is possible to
allow or disallow any command as dictated by the security needs.
Table 9-31 MGCP commands
Call Agent Commands
Gateway Commands
EndpointConfiguration (EPCF)
Notify (NTFY)
NotificationRequest (RQNT)
DeleteConnection (DLXC)
CreateConnection (CRCX)
RestartInProgress (RSIP)
ModifyConnection (MDCX)
DeleteConnection (DLCX)
AuditEndpoint (AUEP)
AuditConnection (AUCX)
In addition, it is possible to define additional proprietary commands, as well as
whether to allow or block those commands. By default, all undefined commands
are blocked.
VPN-1 verifies that the new commands are RFC compliant.
MGCP packets contain an optional SDP header. This header contains information
such as the destination port number, the destination IP address and the media type
(audio or video). The predefined MGCP commands MDCX and CRCX have an SDP
header.
306
Securing MGCP-Based VoIP
When defining an MGCP command, it is possible to specify whether or not the
command contains an SDP header. VPN-1 knows how to parse the header and
check it has the correct syntax. If the destination address and port in the header
are allowed, VPN-1 allows the media connection through the Gateway.
Verify MGCP Header Content
Use this option to block binary characters, in order to prevent executable binary
files being sent in the MGCP headers. This option also blocks various potentially
dangerous control characters and the null character.
Allow Multicast RTP Connections
RTP is the protocol used for VoIP media. Multicast RTP can be used for radio. If a
server sends a packet with a multicast address, the Media Gateway opens a port,
and any client can listen to multicast on that port. Use this option to block or allow
MGCP multicasts.
Secured MGCP Topologies and NAT Support
VPN-1 supports the MGCP deployments listed in Table 9-1. It is possible to
configure NAT (either Hide or Static) for the phones in the internal network, and
(where applicable), for the Call Agent.
Table 9-32 Supported MGCP Topologies
No NAT
NAT for Phones Hide/Static NAT
NAT for the Call
Agent - Static
NAT
Peer-to-Peer
(Figure 9-4)
Yes
Yes
Not applicable
Proxy in External
(Figure 9-5)
Yes
Yes
Not applicable
The “Call Agent” is any MGCP handover device.
Where there is one or more handover devices, the signalling passes through one or
more Call Agents. Once the call has been set up, the media can pass peer to peer.
The SmartDashboard configuration depends on the topology, as described in
“Configuring MGCP-Based VoIP” on page 309 which includes diagrams showing
the most widely used deployment topologies.
Chapter 9
Securing Voice Over IP (VoIP) 307
Securing MGCP-Based VoIP
Figure 9-23 MGCP Call Agent in Internet with NAT for Internal phones
Additional Conditions for Using NAT in MGCP Networks
MGCP can be used with Network Address Translation (NAT), subject to the
following conditions:
•
Hide NAT can be used for all types of calls (incoming, outgoing, internal and
external). However, Manual Hide NAT rules cannot be used with Hide NAT for
incoming calls. For security reasons, when using Hide NAT for incoming calls,
the Destination of the VoIP call in the appropriate rule in the Security Rule
Base cannot be Any.
•
Where both endpoints are on the trusted side of the VPN-1 gateway, calls
cannot be made from the same source to two endpoints, where one endpoint is
NATed (either Static or Hide) and the other is not.
•
Bidirectional NAT of VoIP calls is not supported.
Synchronizing User Information
The user IP Phone sends MGCP messages to the Call Agent in order to register
itself on the network. Once a phone is registered, it can make calls. These MGCP
messages cross VPN-1, and are then stored in the user database.
Registration makes it possible to initiate calls from outside the VPN-1 gateway to
phones whose addresses are translated using Hide NAT.
If the VPN-1 machine is rebooted, the VoIP user database is deleted. The
cpstop/cpstart commands do not delete the user database.
308
Securing MGCP-Based VoIP
Configuring MGCP-Based VoIP
MGCP Rules for a Call Agent in the External Network
An MGCP topology with a Call Agent in the external network is shown in Figure 9-7.
The following procedure explains how to allow bidirectional calls between the
MGCP phones in the internal network (Net_A) and phones in an external network
(Net_B), and how to define NAT for the internal phones.
Figure 9-24 MGCP Call Agent in External Network
To define an MGCP rule for a call agent in the external network:
1. Define the network objects (Nodes or Networks) for the IP Phones that are
managed by the Handover device (MGCP Call Agent) and are allowed to make
calls, and whose calls are tracked by the VPN-1 Gateway.
For the example in Figure 9-24, these are Net_A and Net_B.
2. Define the network object for the Handover device (MGCP_Call_Agent).
3. Define the VoIP domain object. If the Call Agent (MGCP_Call_Agent) is on one
machine with a single IP address, define only one VoIP domain. If there are
different IP addresses, define a VoIP domain for each IP address.
Right-click the Network Objects tree, and select New… > VoIP Domains > VoIP
Domain MGCP Call Agent.
Chapter 9
Securing Voice Over IP (VoIP) 309
Securing MGCP-Based VoIP
Table 9-33
VoIP Domain Definition
With Handover
Name
VoIP_Domain
Related endpoints domain
Group containing Net_A and
Net_B
VoIP Gateway installed at
MGCP_Call_Agent
4. Now define the rules. With full handover enforcement, define the following rule:
Table 9-34
Source
Destination
Service
Action
VoIP_Domain
Net_A
Net_A
VoIP_Domain
mgcp_CA or
mgcp_MG or
mgcp_dynamic_ports
Accept
The services are:
•
mgcp_CA is Call Agent service. It uses port 2727.
•
mgcp_MG is the Media Gateway service. It uses port 2427.
•
mgcp_dynamic_ports - is the MGCP service and uses ports that are not
predefined. For example, ports that were identified in the NotifiedEntity
field in previous MGCP packets.
5. To define Hide NAT (or Static NAT) for the phones in the internal network, edit
the network object for Net_A. In the NAT tab, check Add Automatic Address
Translation Rules, and select the Translation method (Hide or Static)
6. Configure the SmartDefense options under Application Intelligence > VoIP >
MGCP as required.
7. Install the security policy.
310
Securing SCCP-Based VoIP
Securing SCCP-Based VoIP
Note - Before reading this section, read “Introduction to the Check Point Solution for
Secure VoIP” on page 249 to “Protocol-Specific Security” on page 258.
The SCCP protocol is described in this section only to the extent required to secure SCCP traffic using
VPN-1.
In This Section
The SCCP Protocol
page 311
SCCP Devices
page 312
SCCP Network Security and Application Intelligence
page 312
ClusterXL Support for SCCP
page 313
Configuring SCCP-Based VoIP
page 313
The SCCP Protocol
Many Cisco® devices use the Cisco proprietary VoIP protocol, SCCP (Skinny Client
Control Protocol). The SCCP protocol is also licensed to a number of Cisco
partners.
SCCP uses TCP on port 2000 for the control signals. Media is transmitted using
RTP over UDP to and from a SCCP client or H.323 terminal for audio.
The protocol headers are binary headers (unlike MGCP, for example, which uses
text headers).
The SCCP protocol defines hundreds of messages. They can be broadly divided into
three groups:
•
Registration and management messages.
•
Media Control Messages.
•
Call Control Messages.
Chapter 9
Securing Voice Over IP (VoIP) 311
Securing SCCP-Based VoIP
SCCP Devices
SCCP has a centralized call-control architecture. The CallManager manages SCCP
clients (VoIP endpoints), which can be IP Phones or Cisco ATA analog phone
adapters. The CallManager controls all the features of the endpoints. It requests
information, such as the station capabilities, and sends information, such as the
button template and the date/time, to the VoIP endpoints.
The CallManagers are defined in SmartDashboard, usually as Node objects. The
networks containing directly-managed IP Phones are also defined in
SmartDashboard. There is normally no need to define network objects for individual
phones. Cisco ATA devices that are managed by a CallManager must be defined in
SmartDashboard, but the connected analog phones are not defined.
To allow SCCP conversations, you need only create rules to allow the SCCP control
signals through the VPN-1 Gateway. There is no need to define a rule for the media
that specifies which ports to open and which endpoints will talk. VPN-1 derives this
information from the signalling. Given a particular VoIP signalling rule, VPN-1
automatically opens ports for the endpoint-to-endpoint RTP/RTCP media stream.
SCCP Network Security and Application
Intelligence
VPN-1 provides full connectivity and network level and security for SCCP-based
VoIP communication. All SCCP traffic is inspected and legitimate traffic is allowed
to pass while attacks are blocked. All VPN-1 capabilities are supported, such as
anti- spoofing and protection against DoS attacks. Fragmented packets are
examined and secured using kernel-based streaming. However, NAT on SCCP
devices is not supported.
VPN-1 restricts handover locations, and controls signalling and data connections,
as described in “VoIP Application Intelligence” on page 253.
VPN-1 tracks state and verifies that the state is valid for all SCCP message. For a
number of key messages, it also verifies of existence and correctness of the
message parameters.
SmartDefense can perform additional content security checks for SCCP
connections, thereby providing a greater level of protection.
Under Application Intelligence > VoIP > SCCP, two options are available:
•
312
Verify SCCP Header Content blocks various potentially dangerous control
characters, and the null character.
Securing SCCP-Based VoIP
•
Block Multicast RTP Connections blocks SCCP multicasts. RTP is the protocol
used for VoIP media. Multicast RTP can be used for radio. If a server sends a
packet with a multicast address, the CallManager opens a port, and any client
can listen to multicast on that port.
ClusterXL Support for SCCP
SCCP calls can be made across a ClusterXL Gateway cluster. However, calls do not
survive failover if the failover occurs while the call is being set up.
Configuring SCCP-Based VoIP
To configure SCCP-Based VoIP:
1. Configure the SmartDefense settings for SCCP under Application Intelligence >
VoIP > SCCP.
2. Define the network objects (Nodes or Networks) for the Cisco ATA devices or IP
Phones that are controlled by the CallManagers.
3. Define a Group object for the VoIP endpoint domain. This is a group all the
network objects defined in step 2.
4. Define the network object for the machine on which the CallManager is
installed.
5. Define the VoIP domain object.
From the SmartDashboard menu, select Manage > Network Objects > New… >
VoIP Domains > VoIP Domain SCCP. Give the Domain object a Name. For the
Related endpoints domain, select the Group object defined in step 3. For the
VoIP installed at option, select the network object defined in step 4.
6. Define the VoIP Rule(s) that are appropriate for the topology. Place the
predefined SCCP service in the Service column of the rule. SCCP interoperates
with other VoIP protocols. However, SCCP configuration is independent of the
other VoIP protocol configuration. Define separate rules for SCCP and the other
VoIP protocols.
The rules depend on the network topology. For details, refer to the following
sections:
•
“SCCP Rules for a CallManager in the DMZ” on page 314.
•
“SCCP Rules for a CallManager in the Internal Network” on page 315.
•
“SCCP Rules for a CallManager in an External Network” on page 316.
Chapter 9
Securing Voice Over IP (VoIP) 313
Securing SCCP-Based VoIP
7. Install the security policy.
SCCP Rules for a CallManager in the DMZ
In a DMZ topology shown in Figure 9-25, the Cisco ATA devices or IP Phones are in
the internal and external networks, and the CallManager is in a DMZ network
connected to a separate interface of the VPN-1 gateway.
Figure 9-25 SCCP CallManager in the DMZ
The rules in Table 9-35 allows any telephone managed by ATA_Int and ATA_Ext to
make calls to each other.
Table 9-35 SCCP rules for a CallManager in the DMZ
Source
Destination
Service
Action
ATA_Int
ATA_Ext
VoIP_Call_Manager
SCCP
Accept
VoIP_Call_Manager
ATA_Int
ATA_Ext
SCCP
Accept
VoIP_Call_Manager is the VoIP domain object with endpoint domain that includes
both ATA_Int and ATA_Ext. Create the VoIP domain object as shown in Figure 9-26.
Add both Cisco ATA device or IP Phone objects to a Group object, and use it as the
Related endpoints domain. In the VoIP installed at field, put the CallManager object.
314
Securing SCCP-Based VoIP
Figure 9-26 VoIP Domain of the SCCP CallManager
SCCP Rules for a CallManager in the Internal Network
In the topology shown in Figure 9-27, there are Cisco ATA devices or IP Phones in
the internal network and in an external network. The CallManager is in the internal
network.
Figure 9-27 SCCP CallManager in an Internal Network
Chapter 9
Securing Voice Over IP (VoIP) 315
Securing SCCP-Based VoIP
The rules in Table 9-36 allow any telephone managed by ATA_Int and ATA_Ext to
make calls to each other. Each rule allows calls in one direction.
Table 9-36 SCCP Rules for a CallManager in the internal Network
Source
Destination
Service
Action
Comment
VoIP_Call_Manager
ATA_Ext
SCCP
Accept
Outgoing calls
ATA_Ext
VoIP_Call_Manager
SCCP
Accept
Incoming calls
VoIP_Call_Manager is the VoIP domain object with an endpoint domain that
includes both ATA_Int and ATA_Ext. Create the VoIP domain object as shown in
Figure 9-26 on page 315. Add both Cisco ATA device or IP Phone objects to a
Group object, and use it as the Related endpoints domain. In the VoIP installed at
field, put the CallManager object.
SCCP Rules for a CallManager in an External Network
In the topology shown in Figure 9-28, there are Cisco ATA devices or IP Phones in
the internal network and in an external network. The CallManager is in the external
network.
Figure 9-28 SCCP CallManager in an External Network
316
Securing SCCP-Based VoIP
The first rule in Table 9-37 allows any telephone managed by ATA_Int and in the
Skinny_LAN to call any telephone managed by ATA_Ext. The second rule allows
calls in the opposite direction. In this case, no VoIP domain is needed, because the
CallManager is in the external network. Make sure that, in the VPN-1 Gateway
object Topology page, the interface that faces the Internet is defined as External.
Table 9-37 SCCP rules for a CallManager in the internal network
Source
Destination
Service
Action
Comment
ATA_Int
Skinny_LAN
Call_Manager
SCCP
Accept
Outgoing calls
Call_Manager
ATA_Int
Skinny_LAN
SCCP
Accept
Incoming calls
Allowing Internal Calls When the CallManager is in an External
Network
If the CallManager is in an external network, and you want to allow internal calls
between phones managed by different Cisco ATA devices or IP Phones behind the
same interface of the VPN-1 Gateway, you must define a VoIP domain. This
configuration is illustrated in Figure 9-28 on page 316. The rules in Table 9-38
allow calls between ATA_Int and the IP Phones in Skinny_LAN.
Table 9-38 SCCP rules for a CallManager in the internal network
Source
Destination
Service
Action
Comment
ATA_Int
Skinny_LAN
VoIP_Call_Manager
SCCP
Accept
Outgoing calls
VoIP_Call_Manager
ATA_Int
Skinny_LAN
SCCP
Accept
Incoming calls
VoIP_Call_Manager is the VoIP domain object with an endpoint domain that
includes both ATA_Int and Skinny_LAN. Create the VoIP domain object as shown in
Figure 9-26 on page 315. Add both Cisco ATA device or IP Phone objects to a
Group object, and use it as the Related endpoints domain. In the VoIP installed at
field, put the CallManager object.
Chapter 9
Securing Voice Over IP (VoIP) 317
Securing SCCP-Based VoIP
318
10
Chapter
Securing Instant Messaging
Applications
In This Chapter
The Need to Secure Instant Messenger Applications
page 320
Introduction to Instant Messenger Security
page 321
Understanding Instant Messenger Security
page 322
NAT Support for MSN Messenger over SIP
page 323
NAT Support for MSN Messenger over MSNMS
page 324
Logging Instant Messenger Applications
page 324
Configuring SIP-based Instant Messengers
page 325
Configuring MSN Messenger over MSNMS
page 327
Configuring Skype, Yahoo and ICQ and Other Instant Messengers page 328
319
The Need to Secure Instant Messenger Applications
The Need to Secure Instant Messenger
Applications
Common Instant Messenger capabilities include file transfer, remote collaboration,
and remote assistance. File transfers, for example, are a potential source of virus
and worm infections. Traditional content filters do not look for Instant Messenger
traffic and, as a result most of the new worms and Trojans, use Instant Messenger
and peer-to-peer networks to propagate. Remote assistance allows help desk staff
to control the PC to improve service and reduce MIS costs. However, it can also be
used by hackers to take control of a remote computer.
Instant Messaging protocols themselves have vulnerabilities that can be exploited
to cause a Denial of Service attack. For example, passing an overly long user name
and password for authorization for some applications may cause a buffer overflow
that could bring down the Instant Messenger server.
SIP is emerging as the de-facto standard for instant messaging applications in the
enterprise. There are several known security issues associated with SIP-based
instant messaging applications. These are similar to the vulnerabilities associated
with SIP when used for Voice Over IP (VoIP), with additional vulnerabilities caused
by the nature of Instant Messengers and the way that they are used in the
enterprise.
320
Introduction to Instant Messenger Security
Introduction to Instant Messenger Security
Instant Messenger applications allow communication and collaboration between
users employing various communication modes, such as Instant Messaging, Voice
and Video, Application Sharing, White board, File Transfer, and Remote Assistance.
Firewall and SmartDefense provide powerful and flexible security for Instant
Messengers. MSN Messenger in particular, both in its SIP mode of operation, and
using the native MSNMS protocol, can be secured with an extra level of granularity.
It is possible to selectively block audio, video or other selected capabilities of
MSN Messenger. In addition, the audio and video streams of any SIP-based Instant
Messaging application can be blocked. The Security Rule Base can be used to
allow communication to and from specified locations.
Firewall and SmartDefense secure MSN Messenger over SIP topologies. MSN
Messenger over SIP requires the use of a SIP proxy, and does not support endpoint
-to-endpoint calls.
Chapter 10
Securing Instant Messaging Applications 321
Understanding Instant Messenger Security
Understanding Instant Messenger Security
To understand the principles of securing SIP-based Instant Messenger
communication, refer to Chapter 9, “Securing Voice Over IP (VoIP)”: “Introduction
to the Check Point Solution for Secure VoIP” on page 249 to “Securing SIP-Based
VoIP” on page 259 (inclusive).
VPN-1 dynamically opens ports for the services used by Instant Messenger
applications. It keeps those ports open only for as long as required, and closes
them as soon as the call ends, without waiting for a time-out. The order and
direction of the packets is also enforced.
For detailed information about MSN Messenger and the protocols it uses, visit the
following Microsoft web pages:
•
http://www.microsoft.com/technet/prodtechnol/winxppro/evaluate/insid01.mspx
•
http://www.microsoft.com/technet/prodtechnol/winxppro/plan/rtcprot.mspx
(recommended for technical reference)
Some peer-to-peer applications also have Instant Messenger capabilities, which can
be blocked or allowed. For details, see the HTML pages and online help for the
SmartDefense Application Intelligence > Peer to Peer category.
322
NAT Support for MSN Messenger over SIP
NAT Support for MSN Messenger over SIP
The Firewall and SmartDefense components of VPN-1 allow all SIP-based MSN
Messenger applications to work seamlessly with Static Network Address Translation
(NAT). Hide NAT is fully supported for Instant Messenger (chat) and audio
connections. For other MSN Messenger applications, some Hide NAT operations are
not supported due to the inconsistent behavior of MSN Messenger. Table 10-1
shows how Hide NAT can be used with SIP-based MSN Messenger applications.
Table 10-1 Support for Hide NAT with SIP-Based MSN Messenger Capabilities
Hide NAT
Instant
Messaging
Application
Sharing
and
Whiteboard
File
Transfer
and
Remote
Assistance
Audio
Video and
Audio
Internal –> External
(outbound traffic)
Yes
Yes
No
Yes
No
External –> Internal
(inbound traffic)
Yes
No
Yes
Yes
No
Internal –> Internal
(internal traffic)
Yes
Yes
Yes
Yes
Yes
Chapter 10
Securing Instant Messaging Applications 323
NAT Support for MSN Messenger over MSNMS
NAT Support for MSN Messenger over
MSNMS
For MSN Messenger over MSNMS, Static and Hide Network Address Translation
(NAT) are supported for the Instant Messenger and File Transfer applications.
Logging Instant Messenger Applications
VPN-1 provides detailed protocol-specific logs for Instant Messenger conversations.
The following events are logged in SmartView Tracker:
Table 10-2 Logged MSN Messenger over SIP Events in SmartView Tracker
Event or Application
SmartView Tracker
Field name
Value
Call registration
registered IP-phones
SIP address
Instant message
media type
instant messaging
Audio
media type
Audio
Video
media type
Video
Application sharing and Whiteboard
(MSN Messenger only)
media type
Application
File transfer
(MSN Messenger only)
media type
File_Transfer
Remote Assistant
(MSN Messenger only)
media type
Remote_Assistanc
e
The ports used when setting up and maintaining an Instant Messenger call can be
either fixed or dynamically assigned. They depend on the call setup sequence,
which varies with the event and application. The Service and Source Port fields of
the SmartView Tracker log record show the port numbers used.
324
Configuring SIP-based Instant Messengers
Configuring SIP-based Instant Messengers
The Firewall and SmartDefense components make it possible to block or allow all
SIP-based Instant Messenger applications. For MSN Messenger over SIP, additional
granular control is possible.
Note - To understand how to configure SmartDashboard for a SIP Proxy topology, it is
highly recommended to first read “Configuring SIP-Based VoIP” on page 269.
To completely block MSN Messenger over SIP and other SIP-based Instant
Messenger applications, including the core instant messaging capabilities, do not
allow the SIP service in the Security Rule Base.
To selectively block SIP-based Instant Messenger applications (while allowing the
core instant Messaging capabilities):
1. Create a network group object that contains all clients that are allowed to work
with the SIP proxy (call it allowed_phones, for example).
2. Create a VoIP domain object for the SIP proxy (call it SIP_domain, for
example).
3. Define the rule that includes all the services that you wish to allow. The rule in
Table 10-3 includes all the relevant services, and allows calls in both
directions.
Table 10-3 Example rule allowing SIP-based Instant Messengers
Source
Destination
Service
Action
Action
allowed_phones
SIP_domain
SIP_domain
allowed_phones
sip
sip_dynamic_ports
T.120
MSN_Messenger_File_Transfer
Accept
Log
The relevant services are:
•
sip allows the use of a proxy server and enforces handover via a VoIP
Domain. See “SIP Services” on page 267.
•
sip_dynamic_ports is required for all SIP-based instant messaging
applications.
•
T.120 is needed for application sharing and whiteboard applications.
•
MSN_Messenger_File_Transfer is used for the MSN Messenger File Transfer
application.
Chapter 10
Securing Instant Messaging Applications 325
Configuring SIP-based Instant Messengers
4. If required, configure Static and/or Hide NAT for MSN Messenger, taking into
account the limitations described in “NAT Support for MSN Messenger over
SIP” on page 323.
5. Configure the options under SmartDefense Application Intelligence > VoIP > SIP.
They apply for all SIP-based Instant Messengers such as MSN Messenger over
SIP:
•
Block SIP-based video blocks or allows all applications that use SIP to carry
video. This includes the video components of MSN Messenger, when it is
configured to use SIP. The default setting is not to block.
•
Block SIP-based audio blocks or allows all applications that use SIP to carry
audio. This includes the audio components of MSN Messenger when it is
configured to use SIP. The default setting is not to block.
•
Block SIP-based Instant Messaging blocks or allows all applications that use
SIP for instant messaging. The default setting is to block.
6. To selectively block applications provided by MSN Messenger over SIP,
configure the options in Application Intelligence > Instant Messengers > MSN
Messenger over SIP, as follows
326
•
Block file transfer rejects access to applications that transfer files.
•
Block application sharing rejects access to applications that share files.
•
Block white board rejects access to the White Board applications.
•
Block remote assistant rejects access to your computer with a remote
application
Configuring MSN Messenger over MSNMS
Configuring MSN Messenger over MSNMS
To completely block MSN Messenger over MSNMS, including its core instant
messaging capabilities, do not allow the MSNMS service in the Security Rule Base.
To selectively block MSNMS-based Instant Messenger applications (while allowing
its core instant messaging capabilities):
1. Define a Security Rule Base rule that allows the following services:
•
MSNMS, DNS (group), Microsoft-ds, https.
•
To allow MSN Messenger games, also allow http.
2. If required, configure Static and/or hide NAT for MSN Messenger, taking into
account the limitations described in “NAT Support for MSN Messenger over
MSNMS” on page 324.
3. Configure the SmartDefense
•
MSN Messenger over MSNMS
page, as follows:
Block video prevents the use of MSN Messenger video applications.
Note - The Block video option applies to the Video conferencing application. The Webcam
application (which uses dynamic ports) is always blocked, unless there a specific rule that
allows it.
•
Block audio prevents the use of MSN Messenger audio applications.
•
Block file transfer prevents the use of MSN Messenger file transfer
applications.
•
Block application sharing prevents the sharing of applications through MSN
Messenger.
•
Block white board prevents the use of MSN Messenger White Board
applications.
•
Block remote assistant prevents the use of MSN Messenger White Board
remote assistance applications.
4. To block MSN messenger communication that uses HTTP, in the Web
Intelligence tab, under HTTP Protocol Inspection > Header Rejection, select the
MSN Messenger options.
Chapter 10
Securing Instant Messaging Applications 327
Configuring Skype, Yahoo and ICQ and Other Instant Messengers
Configuring Skype, Yahoo and ICQ and Other
Instant Messengers
328
•
To allow Skype, Yahoo and ICQ and other Instant Messenger applications, follow
the instructions provided by the application vendors.
•
To block Skype, Yahoo! Messenger and ICQ, configure the SmartDefense
options under Application Intelligence > Instant Messengers.
•
Some peer-to-peer applications also have instant messaging capabilities. Block
or allow peer-to-peer applications using the options in Application Intelligence >
Peer to Peer.
Chapter
Microsoft Networking
Services (CIFS) Security
11
In This Chapter
Securing Microsoft Networking Services (CIFS)
page 330
Restricting Access to Servers and Shares (CIFS Resource)
page 331
329
Securing Microsoft Networking Services (CIFS)
Securing Microsoft Networking Services
(CIFS)
CIFS (Common Internet File System) is a protocol used to request file and print
services from server systems over a network. CIFS is an extension of the Server
Message Block (SMB) protocol. CIFS is used as the underlying transport layer for
the NETBIOS session (nbsession) service over TCP using port 139. In Windows
networking, CIFS is used over the Microsoft-DS protocol (port 445) for networking
and file sharing. More information on CIFS can be found at http://samba.org/cifs/.
By default, a Windows server has default shares open for administrative purposes
(C$, ADMIN$, PRINT$) and is therefore an easy target for internal attacks, such as
brute-force password attacks on file servers.
VPN-1 secures Microsoft Networking Services in the Inspection Module, without
requiring a Security server. This meets the high performance requirements of LAN
security (Fast Ethernet and Gigabit Ethernet).
The CIFS resource can be used to enforce the following security checks on CIFS
connections:
330
•
Verifying the correctness of the protocol.
•
Preventing CIFS and NETBIOS messages issued by the client from pointing to
beyond message boundaries.
•
Restricting access to a list of CIFS servers and disk shares.
•
Logging disk share access.
Restricting Access to Servers and Shares (CIFS Resource)
Restricting Access to Servers and Shares
(CIFS Resource)
To restrict access to servers and shares:
1. Define a new CIFS Resource.
2. Configure the CIFS Resource. Allowed Disk\Print Shares is a list of allowed CIFS
servers and disk shares. Note that the use of wildcards is allowed. Select Add,
Edit or Delete to modify the list.
For example, to allow access to the disk share PAUL on the CIFS server
BEATLES:
a. Click Add and type BEATLES in the Server Name field and IPC$ in the Share
Name field. Click OK.
b. Click Add again and type BEATLES in the Server Name field and PAUL in
the Share Name field. Click OK.
3. Add a new rule. Under Service, add either nbsession or Microsoft-DS, together
with the configured Resource.
Warning - Do not delete or change the protocol type of the service objects that perform
content inspection. If the service is altered in this way, the protection will not work.
4. Install the security policy.
Chapter 11
Microsoft Networking Services (CIFS) Security 331
Restricting Access to Servers and Shares (CIFS Resource)
332
Chapter
FTP Security
12
In This Chapter
Introduction to FTP Content Security
page 334
FTP Enforcement by the VPN-1 Kernel
page 334
FTP Enforcement by the FTP Security Server
page 335
Configuring Restricted Access to Specific Directories
page 337
333
Introduction to FTP Content Security
Introduction to FTP Content Security
Content Security for FTP connections is provided both by the VPN-1 kernel and the
FTP Security server. CVP checking can be performed on FTP traffic. This is done by
redirecting the FTP traffic to a CVP server. This is configured in the FTP Resource
object.
FTP Enforcement by the VPN-1 Kernel
The VPN-1 kernel enforces RFC-compliant use of the PORT commands issued by
the client to ensure that no arbitrary syntax is sent. VPN-1 enforces additional
security limitations, including:
334
•
Proper use of the IP field in the PORT command. This verifies that an IP
address presented in a PORT command is identical to the source address of the
client. This protects against the FTP bounce attack. A monitor-only setting for
this protection is available using SmartDefense (Application Intelligence > FTP >
FTP Bounce).
•
Proper use of the port in the PORT command. Data connections to well-known
ports are not allowed.
•
Unidirectional data flow on the data connections. This is a second line of
defense to avoid using the data connection for non-FTP data that require
bi-directional data flow.
FTP Enforcement by the FTP Security Server
FTP Enforcement by the FTP Security Server
The FTP Security server provides a number of capabilities, as described in the
following sections.
Control Allowed Protocol Commands
Only a predefined list of FTP commands is allowed, providing full control over the
character of the FTP traffic. Certain seldom-used FTP commands may compromise
FTP application security and integrity, and may be blocked accordingly. These
include the SITE, REST, and MACB commands, as well as mail commands such as
MAIL and MSND. The SITE command is enabled once, upon login, to allow
common FTP applications to work properly. Allowed FTP commands are controlled
via SmartDefense (Application Intelligence > FTP > FTP Security Server > Allowed FTP
Commands).
VPN-1 enables control over the desired mode of FTP traffic, both for passive FTP,
where the client initiates the data connection, and for active FTP, where the server
initiates the data connection. Typically, the firewall should block connections
initiated from outside the protected domain.
Maintaining Integrity of Other Protected Services
The FTP Security server validates the random ports used by the FTP client or by the
FTP Security server in the PORT command. This prevents the random selection of
a port that is in use by a defined service. This protects against the risk of data
connection initiation to another active/working service in the protected domain.
Avoiding Vulnerabilities in FTP Applications
An attack could be placed in the value of the PORT command. PORT commands
are usually interpreted using string manipulation functions that cause security
risks. The FTP Security server performs a sanity validation for the PORT command
parameter.
Chapter 12
FTP Security 335
FTP Enforcement by the FTP Security Server
Content Security via the FTP Resource
FTP connections can be inspected for viruses and malicious content through
integration with third-party, OPSEC-certified CVP and UFP applications. For
additional information, refer to “Using CVP for Virus Scanning on FTP Connections”
on page 346.
336
Configuring Restricted Access to Specific Directories
Configuring Restricted Access to Specific
Directories
It is possible to allow only file downloads (by specifying GET as an allowed method)
or only uploads (by specifying PUT as an allowed method), or both, in an FTP
resource.
It is also possible to restrict connections to a particular path and/or filename. This
protects against exposure of the FTP server's file system.
The following procedure restricts access to a specific directory on the FTP server
when uploading files from the internal network, but allows files to be downloaded
from anywhere on the FTP server to the internal network.
Two resources must be created. One for upload, and another for download.
To restrict access:
1. Create an FTP Resource to allow file downloads (Manage > Resources, click New
> FTP...).
In the General tab, name the resource (for example, Download), and select a
Tracking Option (such as Log).
In the Match tab, type the allowed directory path using wildcards, for example,
* to allow any directory and filename. Under Methods, select GET.
2. Create an FTP Resource to allow file uploads.
In the General tab, name the resource (for example, Upload), and select a
Tracking Option.
In the Match tab, type the allowed directory path and filename, using wildcards.
For example /uploads/*. Under Methods, select PUT.
Chapter 12
FTP Security 337
Configuring Restricted Access to Specific Directories
Define one rule to allow file uploads, and another rule to allow file downloads. For
a LAN called Alaska_LAN and an FTP server in the DMZ called Alaska.DMZ.ftp, the
rules should resemble those listed in Table 12-1.
Table 12-1 Example Rules for FTP Upload and Download
Source
Destination
Service
Action
Track
Install On
Time
Comment
Alaska
_Lan
Alaska.DMZ
.ftp
ftp->Upload
Accept
Log
*Policy
Targets
Any
ftp
upload to
/uploads/*
Alaska
_Lan
Alaska.DMZ
.ftp
ftp->Upload
Accept
Log
*Policy
Targets
Any
ftp
download
from*
3. Install the security policy.
338
Chapter
Content Security
13
In This Chapter
The Need for Content Security
page 340
Check Point Solution for Content Security
page 341
Configuring Content Security
page 352
Advanced CVP Configuration: CVP Chaining and Load Sharing
page 361
339
The Need for Content Security
The Need for Content Security
Protecting corporate resources is a major concern for most businesses. Blocking
undesirable content is an important part of a corporate security policy for a variety
of reasons, including::
•
Computer viruses, Trojans and ActiveX components containing malicious code
can bring down entire networks.
•
Viewing undesirable web content wastes time and resources.
Access control firewalls prevent unauthorized traffic from passing through the
gateway. However, hackers also attempt to misuse allowed traffic and services.
Some of the most serious threats in today's Internet environment come from attacks
that attempt to exploit the application layer. Access control devices cannot easily
detect malicious attacks aimed at these services.
340
Check Point Solution for Content Security
Check Point Solution for Content Security
In This Section
Introduction to Content Security
page 341
Security Servers
page 342
Deploying OPSEC Servers
page 343
CVP Servers for Anti-Virus and Malicious Content Protection
page 344
Using URL Filtering to Limit Web Surfers
page 348
The TCP Security Server
page 351
Introduction to Content Security
VPN-1 provides Content Security by integrating with best-of-breed, OPSEC-certified
applications that are complement with VPN-1 Content Security capabilities. OPSEC
applications enable organizations to select content screening applications that best
meet their needs, while managing Content Security centrally. These applications:
•
Protect against network viruses, by scanning data and URLs to prevent viruses,
malicious Java and ActiveX components, and other malicious content from
entering your organization.
•
Prevent users from browsing to undesirable web sites, by filtering URLs.
•
Provide auditing capabilities and detailed reports.
For a listing of OPSEC Content Security solutions, refer to:
http://www.opsec.com/solutions/sec_content_security.html.
Content security applications, like virus scanners, inspect the content of individual
packets for specific services.
The Content Vectoring Protocol (CVP) is an API specification developed by Check
Point used for integration with anti-virus servers. This API defines an asynchronous
interface to server applications that validate file content. An important feature of
CVP is scanning files for viruses or harmful applets as they pass through firewalls.
CVP defines a client/server relationship that enables different VPN-1 gateways to
share a common content validation server.
The URL Filtering protocol (UFP) blocks user access to forbidden web sites,
allowing administrators to define undesirable or inappropriate types of web sites.
No configuration is required at the client machine. UFP is useful for companies
that wish to avoid a loss of employee productivity.
Chapter 13
Content Security 341
Check Point Solution for Content Security
In Service Provider environments, it can be offered as an add-on to Internet
services, where it may be used for parental restriction of child web surfing or on
behalf of businesses that have an inherent distrust of Internet content.
Security Servers
Security servers are Check Point processes that are integrated into VPN-1. They are
user mode processes that provide content security for:
•
HTTP
•
FTP
•
SMTP
There is also a generic TCP Security server. Security servers employ many ways of
enforcing Content Security, including, checking whether the connections for these
protocols are well formed, stripping script tags for HTTP, email address translation
for SMTP, and file name matching for FTP.
In addition to Content Security, Security servers also perform authentication. For
additional information on the authentication functions of the Security servers, refer
to “Authentication” on page 59.
How a Security Server Mediates a Connection
Figure 13-1 shows how the Security servers mediate a connection. The HTTP
Security server is used as an example, but the method is the same for all Security
servers.
When a packet is matched to a rule that contains a resource, the Inspection
Module diverts or “folds” a connection to a Security server. The Security server
performs the Application Security checks, and, if necessary, diverts the connection
to a Content Vectoring Protocol (CVP) server application or a URL Filtering (UFP)
server application. The Security server then returns the connection to the
Inspection Module, which opens a second connection that is sent on the
destination HTTP server.
342
Check Point Solution for Content Security
Figure 13-1 How the Security Server Mediates a Connection
The source IP address that appears to the destination server is the IP address of
the client that originally opened the connection. The connection leaves the Security
server with the source IP address of the VPN-1 gateway, and the outbound kernel
performs NAT so that the source IP address is that of the original client.
Deploying OPSEC Servers
OPSEC solutions, such as CVP and UFP servers, are deployed on dedicated servers
(Figure 13-2). These servers are typically placed in the DMZ or on a private network
segment. This allows fast secure connections between the CVP servers and the
VPN-1 gateway.
Performing scanning at the network perimeter is both safer and more efficient than
performing the scanning at the desktop or on the application servers.
Chapter 13
Content Security 343
Check Point Solution for Content Security
Figure 13-2 OPSEC Server Integration with VPN-1
CVP Servers for Anti-Virus and Malicious Content
Protection
In This Section
344
CVP and Anti-Virus Protection for SMTP and HTTP Traffic
page 345
How a Connection is Handled by the HTTP Security Server
page 345
Improving CVP Performance for Web Traffic
page 346
Using CVP for Virus Scanning on FTP Connections
page 346
Check Point Solution for Content Security
CVP and Anti-Virus Protection for SMTP and HTTP
Traffic
To perform virus scanning, the HTTP or SMTP security server transfers packets from
the VPN-1 gateway to another server running an OPSEC certified virus scanner.
This method uses the Content Vectoring Protocol (CVP) to transfer packets to and
from an OPSEC virus scanning server.
The virus scanning CVP server determines if there is a virus. If it finds a virus it
can either:
•
Return the file to the VPN-1 gateway with the offending content removed (if the
CVP server is configured to modify content), or
•
Drop the file (if the CVP server is not allowed to modify content).
CVP uses TCP port 18181, by default.
How a Connection is Handled by the HTTP Security
Server
This section describes how the HTTP Security server handles a connection where
CVP checking is performed. The VPN-1 gateway that runs the HTTP Security server
acts as a proxy, and so is not an active participant in the connection.
The connection request/response process without a CVP server is:
1. HTTP client to HTTP server (request)
2. HTTP server to HTTP client (response)
The data that needs to be checked is carried in the response that comes from the
Web server. Therefore, when a CVP server is used, the response is always checked.
In that case, the connection request/response process is:
1. HTTP client to HTTP server (request)
2. HTTP server to CVP server (response)
3. CVP server to HTTP client (response)
Chapter 13
Content Security 345
Check Point Solution for Content Security
Normally, only HTTP responses, which come from the Web server, are sent to the
CVP server for checking. However, you also may wish to protect against undesirable
content in the HTTP request, for example, when inspecting peer-to-peer
connections. In this case, the connection request/response process is:
1. HTTP client to CVP server (request)
2. CVP server to HTTP server (request)
3. HTTP server to CVP server (response)
4. CVP server to HTTP client (response)
The HTTP Security server can be configured to send HTTP headers to the CVP
server, as well as the HTTP message data.
Improving CVP Performance for Web Traffic
HTTP Security server performance can be significantly improved by ensuring that
safe traffic is not sent to the CVP server. This reducess the number of connections
opened with the CVP server. Nonetheless, sending all content for CVP checking
provides better protection.
VPN-1 considers non-executable picture and video files to be safe because they do
not normally contain viruses.
The HTTP Security server identifies safe content by actually examining the contents
of a file. It does not rely on examining the URL (for file extensions such as *.GIF)
nor does it rely on checking the MIME type (such as image/gif) in the server
response.
For configuration details, refer to “Configuring CVP Checking for Web Traffic with
Improved Performance” on page 356.
Using CVP for Virus Scanning on FTP Connections
Virus scanning on FTP connections can be performed by transferring the file to a
third-party anti-virus application using the CVP protocol.
Figure 13-3 illustrates how VPN-1 implements CVP for virus checking on an FTP
connection.
346
Check Point Solution for Content Security
Figure 13-3 CVP Inspection Process during an FTP Connection
The relevant rule for the connection specifies a resource that includes Content
Vectoring Protocol (CVP) for anti-virus checking.
1. The FTP client establishes a connection via port 21 to the FTP server.
2. The Inspection Module monitors port 21 for GET and PUT commands, and
determines that the CVP server must be invoked.
3. When the client initiates data transfer over port 20, the Inspection Module
folds the connection into the FTP Security server.
4. The FTP Security server sends the file to be inspected to the CVP server.
5. The CVP server scans the FTP files and returns a Validation Result message,
notifying the FTP Security server of the result of the scan.
6. The CVP server returns a clean version of the file to the FTP Security server.
7. Based on the Validation Result message, the FTP Security server determines
whether to transfer the file, and takes the action defined for the resource,
either allowing or disallowing the file transfer.
8. If allowed, the FTP Security server relays the FTP file on to the FTP server.
Chapter 13
Content Security 347
Check Point Solution for Content Security
Using URL Filtering to Limit Web Surfers
In This Section
Understanding URL Filtering
page 348
URL Filtering Using the HTTP Security Server
page 349
Enhanced UFP Performance Mode
page 350
Choosing the URL Filtering Mode
page 351
Understanding URL Filtering
The security administrator can prevent access to specific destinations on the
Internet, allow access only to appropriate web pages, and make it impossible to
access particular web sites, or download certain file types.
This is done using third-party, OPSEC-certified URL SmartCenter applications. The
security administrator can define a corporate security policy that includes URL
screening to block undesirable web pages and to record the types of URLs accessed
for internal analysis and reporting needs.
A URL Filtering Protocol (UFP) serverto maintains a list of URLs and their
categories. When a user requests a URL, VPN-1 checks that URL against a UFP
server, which returns the category under which the URL falls. In SmartDashboard,
permitted categories can be selected. Access to the web page is allowed if the URL
is in a permitted category.
By default, UFP uses TCP port 18182.
Note - A basic URL filtering capability is built in to VPN-1. It can be used to block a
specific list of URLs without a UFP server. For details, refer to “Basic URL Filtering” on
page 380.
VPN-1 can integrate with OPSEC-certified solutions in two ways:
348
•
Enhanced UFP Performance mode (called Enhanced UFP Performance in the URI
Resource) uses VPN-1 kernel inspection together with a dedicated UFP daemon
(aufpd). However, in this mode, it is not possible to use CVP and UFP checking
on the same connection.
•
The ordinary UFP checking mode uses the VPN-1 HTTP Security server to
mediate UFP connections. This can add significantly to the response time
experienced by clients that browse web sites, in comparison to the Enhanced
UFP Performance mode.
Check Point Solution for Content Security
For configuration details, refer to “Configuring URL Filtering with a UFP Server” on
page 356.
URL Filtering Using the HTTP Security Server
Figure 13-4 illustrates how VPN-1 performs URL Filtering of an HTTP connection
using the HTTP Security server and a UFP server.
Figure 13-4 URL Filtering (UFP) Process for an HTTP Connection
1. The client invokes a connection through the VPN-1 Inspection Module.
2. The HTTP Security server uses UFP to send the URL to be categorized to the
third-party UFP server.
3. The UFP server inspects the file and returns a Validation Result message,
notifying the Security server of the result of the inspection.
4. Based on the Validation Result message, the Inspection Module either allows or
disallows the viewing of that particular web page.
Chapter 13
Content Security 349
Check Point Solution for Content Security
Enhanced UFP Performance Mode
Figure 13-5 illustrates how enhanced URL Filtering (UFP) performance of an HTTP
connection works.
Figure 13-5 Enhanced URL Filtering (UFP) Process, Using Kernel Inspection
1. The web client invokes a connection through the VPN-1 Inspection Module.
2. The kernel Inspection Module puts up a barrier that prevents the web clients
receiving a response from the web server before a confirmation is received from
the UFP server.
3. HTTP requests destined for the web server go through VPN-1 uninterrupted.
4. At the same time as step 3, the Inspection Module extracts the URL, and the
AUFPD daemon establishes a UFP session with the UFP server to categorize the
URL.
5. Based on the Validation Result message, AUFPD tells the Inspection Module
whether or not to block the URL.
6. If the URL is permitted, the barrier is removed, and the HTTP response from
the web server is allowed through VPN-1.
7. If the URL is blocked, the HTTP response is rejected.
350
Check Point Solution for Content Security
Choosing the URL Filtering Mode
“Enhanced UFP Performance Mode” and “URL Filtering Using the HTTP Security
Server” are different ways of performing UFP Filtering. When deciding the method
to employ, you must balance performance against security.
When the Enhanced UFP Performance mode is used, users browsing web sites
experience significantly improved response times, as compared to UFP checking
using the VPN-1 HTTP Security server. However, in this mode (called Enhanced UFP
Performance in the URI Resource), it is not possible to use CVP and UFP checking
on the same connection.
The TCP Security Server
Malicious content can potentially be carried in any TCP service, not only SMTP,
HTTP and FTP.
The TCP Security server is used to perform CVP or UFP Content Security by a
third-party, OPSEC-compliant application, on any TCP Service.
For configuration details, refer to“Performing CVP or UFP Inspection on any TCP
Service” on page 360.
Chapter 13
Content Security 351
Configuring Content Security
Configuring Content Security
In This Section
Resources: What They Are and How to Use Them
page 352
Creating a Resource and Using it in the Rule Base
page 353
Configuring Anti-Virus Checking for Incoming Email
page 354
Configuring CVP Checking for Web Traffic with Improved Performance
page 356
Configuring URL Filtering with a UFP Server
page 356
Performing CVP or UFP Inspection on any TCP Service
page 360
Advanced CVP Configuration: CVP Chaining and Load Sharing
page 361
Resources: What They Are and How to Use Them
To perform Content Security via the Security Rule Base, an object called a
Resource is defined in SmartDashboard (Figure 13-6). Resources are used to
match a specific kind of application layer content, in other words, to specify what
content you are looking for, and to perform some action on the content.
Figure 13-6 A URI Resource, Showing the General Tab
Using a Resource turns on either kernel inspection or the Security servers,
depending on what the resource is used for.
352
Configuring Content Security
For instance, a rule can be created that will drop the connection and generate an
alert if there are GETs or PUTs in an FTP transfer or if a specifically named file is
part of the transfer. Another rule can drop email addresses or attachments while
allowing the rest of the content through.
To specify the content you are looking for, regular expressions and wildcards can be
used in the Resource.
The Resource is triggered when a rule includes the Resource, and a packet
matching that rule is encountered. A Resource is applied per Service. If a
connection matches the source and destination of the rule and the match
parameters of the Resource, then both the action in the rule and the action in the
Resource are applied.
Creating a Resource and Using it in the Rule Base
1. To create a resource, select the Resources tab in the objects tree. Select the
Resource Type, right-click, select a resource type, such as New URI... or New
SMTP....
2. Define the resource parameters in the General tab, and in the other tabs as
required.
3. To use a service with a resource in a rule, right-click in the Service column of
the rule, right-click, and select Add with Resource.... In the Service with
Resource window, select the service, and then select the Resource that will
operate on the service. Click OK.
If a connection matches the source and destination of the rule and the match
parameters of the Resource, then both the action in the rule and the action in the
Resource are applied.
Chapter 13
Content Security 353
Configuring Content Security
Configuring Anti-Virus Checking for Incoming Email
The goal is to check incoming mail for viruses, as illustrated in Figure 13-7. SMTP
mail arrives from the Internet to a mail relay server (Mail_relay) in a DMZ segment.
Before the mail is forwarded to the internal mail server (Mail_server), it undergoes
virus checking by the anti virus server (Anti_virus_server). Outgoing mail is sent
from the mail server to the Internet.
Figure 13-7 Sample Configuration - illustrating Anti-Virus Checking for Incoming Email
To configure anti-virus checking for incoming email:
1. Create a host object for the machine on which the third-party, OPSEC server
application is installed.
2. Create an OPSEC Application object to represent the OPSEC Application server,
and associate it with the host object created in step 1.
3. Define an SMTP resource that uses the OPSEC Application object, and
associate it with the OPSEC Application object created in step 2. Specify the
matching, and the content checking to be performed.
4. Define rules that use the resource.
To implement anti-virus checking for incoming email:
1. Create a host object (e.g. Anti_virus_server) for the machine on which the
third-party OPSEC Server application is installed.
2. Create an OPSEC Application object to represent the OPSEC application server,
and associate it with the host object created in step 1. Initialize Secure Internal
Communication between the OPSEC Application and the SmartCenter server. In
the CVP Options tab, verify that FW1_cvp is selected, and click OK.
354
Configuring Content Security
3. Define an SMTP resource that uses the OPSEC object, and associate it with the
OPSEC Application object created in step 2. Specify the matching and the
content checking to be performed.
a. In the General Tab, give the Resource a Name (such as virus_check). Select
both the Mail Delivery and the Error Mail Delivery options, as well as
Exception Tracking.
b. In the Match tab, for the Sender put *, and for the Recipient put
*@your_domain, (for example *@company.com).
c. In the Action1 tab, define the Rewriting Rules, if any.
d. In the Action2 tab, define the Attachment handling, if any. Define the largest
allowed email attachment.
4. In the CVP tab, check Use CVP (Content Vectoring Protocol), select the CVP erver
defined in step 1, and define the CVP Server Options and Reply Order.
Click OK. A message may appear regarding stripping MIME of type
“message/partial'”. Accepting the MIME strip of type “message/partial” will
result in a configuration change to the Action2 tab. The Strip MIME of Type
field will contain message/partial. Stripping the Multipurpose Internet Mail
Extension (MIME) type of message/partial will not allow multiple-part messages
to be accepted for scanning.
5. Define a pair of rules that will perform virus checking on incoming mail, and a
rule to allow outbound email. The rules should look similar to the ones in 6..
6. Install the security policy.
Table 13-1
Source
Destination
Service
Action
Track
Install On
Comment
Any
mail_relay
smtp
Accept
Log
Corporate_gw
Incoming
email
to mail relay
mail_relay
mail_server
smtp->
virus_check
Accept
Log
Corporate_gw
Incoming
email
virus scan
mail_server
Any
smtp
Accept
Log
Corporate_gw
Outgoing email
Chapter 13
Content Security 355
Configuring Content Security
Configuring CVP Checking for Web Traffic with
Improved Performance
The performance of the CVP server when inspecting HTTP connections can be
enhanced by ensuring that only unsafe file types are sent to the CVP server for
inspection. For background information, refer to “Improving CVP Performance for
Web Traffic” on page 346.
To configure CVP checking for web traffic:
1. Create a host object for the machine on which the CVP Server application is
installed.
2. Create an OPSEC Application object to represent the CVP server, and associate
it with the host object created in step 1.
3. Define a URI resource that uses the OPSEC Application object, and associate it
with the OPSEC Application object created in step 2. Give it a name (such as
Internal.HTTP.CVP), specify the matching, and the content checking to be
performed.
4. In the CVP tab, select Send only unsafe file types to the CVP server, and the other
required CVP options.
5. Associate the Resource with the HTTP Service, and place it in a rule in the
Security Rule Base. Refer to the sample rule shown in Table 13-2.
Table 13-2 Sample URI Resource in a Rule Base
Source
Destination
Service
Action
Internal_LAN
Any
http->Internal.HTTP.CVP
Accept
Configuring URL Filtering with a UFP Server
VPN-1 checks web connection attempts using URL Filtering Protocol (UFP) servers.
UFP servers maintain lists of URLs and their appropriate categories (i.e., permitted
or denied).
URL databases can be updated to provide a current list of blocked sites. All
communication between VPN-1 and the URL Filtering server uses the UFP.
356
Configuring Content Security
Rule Match in UFP Modes
There are differences in rule matching behavior between UFP rules in Enforce URI
Capabilities mode (that use the kernel) and rules in Enhance UFP Performance mode
(that use the HTTP Security server). For additional information on these two modes,
refer to “Using URL Filtering to Limit Web Surfers” on page 348.
•
In Enforce URI Capabilities mode, the connection is matched to the Source,
Destination, Service, and UFP category of the Resource in the rule.
If the connection does not match all of these rules, the connection is compared
to successive rules in the Rule Base until a match is found.
•
In Enhance UFP Performance mode, the connection is matched only to the
Source, Destination, and Service in the rule. The connection is not matched to
the UFP category. If the connection matches the Source, Destination, and
Service in the rule, it is not matched to any other rule further down the Rule
Base.
In this mode, if the connection matches the UFP category, the action specified
in the rule is performed. If the connection does not match the UFP category,
the opposite of the Action specified in the Rule is performed.
This means that you can only have one rule with an Enhance UFP Performance
resource, for a given Source, Destination, or Service. In the Match tab of the
resource, you must include all UFP categories. The Action in the rule takes place if
any of the selected categories match the connection.
When using Enforce URI Capabilities mode in a UFP resource, you may have more
than one rule with a resource using this mode, for a given Source, Destination, or
Service. However, to maintain a simpler and less error-prone Rule Base, it is
recommended to use only one resource, as for the Enhance UFP Performance mode.
For example, consider the following rules:
Table 13-3
No.
Source
Destination
Service
Action
1
Any
Any
Resource with UFP Category “Drugs”
Drop
2
Any
Any
Resource with UFP Category “Alcohol”
Drop
If a connection fits the UFP category of “Alcohol”:
•
In Enhance UFP Performance mode, the connection matches Rule 1 and the
connection is Accepted — which is not the desired behavior.
Chapter 13
Content Security 357
Configuring Content Security
•
In Enforce URI Capabilities mode, the connection matches Rule 2 and the
connection is Dropped.
The correct way to build this rule so that it will work in all modes, and for greater
simplicity, is as follows:
Table 13-4
358
No.
Source
Destination
Service
Action
1
Any
Any
Resource with UFP Categories “Drugs”
and “Alcohol”
Drop
Configuring Content Security
Configuring URL Filtering
This procedure describes how to configure a URL Filtering using the VPN-1 kernel
or using the Security server. For background information, refer to “Using URL
Filtering to Limit Web Surfers” on page 348.
1. Create a host object for the machine on which the third-party OPSEC Server
application is installed.
2. Create an OPSEC Application object (Alaska_HTTP_UFP) to represent the
OPSEC application server, and associate it with the host object created in step
1.
3. Create a new URI resource that uses the OPSEC Application object, and
associate it with the OPSEC Application object created in step 2.
4. To perform URL Filtering using the VPN-1 kernel, select Enhance UFP
Performance.
To perform URL Filtering using the Security server, select Enforce URI
capabilities, and select URI Match Specification Type: UFP.
In the Match tab, select the UFP server object that was created in step 2. Check
the appropriate Categories. Some UFP servers show just two categories: Blocked
and Not Blocked. Others show many categories.
Figure 13-8 shows a restrictive resource that matches one of the many
categories.
Figure 13-8 Match tab for a URI Resource for UFP
Chapter 13
Content Security 359
Configuring Content Security
5. Associate the Resource with the HTTP Service, and place it in a rule in the
Security Rule Base. Refer to the sample rules shown in Table 13-5.
The Action in Rule 1 is Drop because the resource matches the Blocked
categories. If the resource matched the Not Blocked categories, the Actions in
Rules 1 and 2 would be reversed: Allow in Rule 1, and Drop in Rule 2.
Rule 2 is required for the Enforce URI Capabilities mode. For the Enhance UFP
Performance mode it is recommended to avoid problems in cases where more
than one URI resource is used in the Rule Base.
Table 13-5 Sample UFP Rule Base Policy
No.
Source
Destination
Service
Action
1
Any
Any
http->Alaska_HTTP_UFP
Drop
2
Any
Any
http
Accept
Performing CVP or UFP Inspection on any TCP
Service
To configure CVP or UFP inspection on any TCP service:
1. In the TCP Service Properties, Advanced tab, check Enable for TCP Resource.
2. Create a TCP Resource. In the General tab, select CVP or UFP, and the Exception
Track method.
3. Configure settings in the CVP or UFP tab.
4. Add a Rule to the Rule Base, and in the Service column, select Add with
Resource.
5. In the Service with Resource window, select the TCP service configured in step
1. under Resource, select the resource created in step 2.
6. Install the security policy.
For additional information, refer to “The TCP Security Server” on page 351.
To configure CVP inspection for email, refer to“Configuring Anti-Virus Checking for
Incoming Email” on page 354.
To configure CVP and UFP inspection for web traffic, refer to “Configuring Web
Content Protection” on page 390.
360
Advanced CVP Configuration: CVP Chaining and Load Sharing
Advanced CVP Configuration: CVP Chaining
and Load Sharing
In This Section
Introduction to CVP Chaining and Load Sharing
page 361
CVP Chaining
page 361
CVP Load Sharing
page 363
Combining CVP Chaining and Load Sharing
page 364
Configuring CVP Chaining and Load Sharing
page 364
Introduction to CVP Chaining and Load Sharing
Traffic that crosses the VPN-1 gateway can be checked using CVP servers. CVP
checking is available for Web, Mail, FTP and TCP traffic. For detailed explanations,
see:
•
“CVP and Anti-Virus Protection for SMTP and HTTP Traffic” on page 345.
•
“Using CVP for Virus Scanning on FTP Connections” on page 346.
It is possible to chain CVP servers in order to combine functionality, and to perform
load sharing between CVP servers, in order to speed up CVP checking.
CVP Chaining
CVP servers can be chained for the purpose of combining functionality. Chaining is
useful when each of the CVP servers performs a different task, such as scanning for
viruses, or blocking large email attachments. In the configuration shown in
Figure 13-9, the VPN-1 Security server invokes the first, second, and third CVP
servers in turn.
Chapter 13
Content Security 361
Advanced CVP Configuration: CVP Chaining and Load Sharing
Figure 13-9 CVP Server Chain
Chained CVP servers are invoked in the order set by the administrator in the CVP
Group object. When choosing a chaining order, consider whether there are any
security or connectivity issues. For example, in Figure 13-9, you may want the virus
scanning to take place first.
The order in which the chained servers are called is relative to the response of the
server. This is the case whether the server is on the unprotected (external interface)
side of the VPN-1 gateway or on the protected (internal interface) side.
For example, in Figure 13-9, consider a user at an internal FTP client who is
downloading a file from an external FTP server. CVP checking is performed on the
response from the FTP server (that is, on the downloaded file) in the order defined
in the CVP Group object.
There is one exception to this order. The HTTP Security server allows CVP checking
to be performed on the HTTP request. CVP checking of HTTP requests is performed
by the CVP servers in the reverse of the order specified in the CVP Group object.
CVP chaining works only if all servers in the chain are available. If one or more of
the servers is unavailable, the whole CVP session is dropped. This is because
skipping one of the servers may contradict the Security Policy. For example, the
Security Policy may specify that both virus scanning and blocking of large
attachments are mandatory.
362
Advanced CVP Configuration: CVP Chaining and Load Sharing
CVP Load Sharing
Identical CVP servers can be configured to share the load among themselves. Load
sharing can speed up CVP checking by allowing many CVP sessions to run
simultaneously on more than one CVP server.
Two load-sharing methods are available:
•
Round robin: The VPN-1 Security server sends each new CVP session to a
different CVP server in turn.
•
Random: The VPN-1 Security server sends each new CVP session to a randomly
chosen CVP server.
It is possible to configure a load-sharing suspension period for a CVP server that
does not respond. During that period of time, that CVP server does not take part in
the load-sharing group.
CVP load sharing is implemented by defining a Resource that invokes a group of
CVP servers. The order in round robin mode is configured in the CVP Group object.
Figure 13-10 shows two CVP servers that share the load.
Figure 13-10Load Sharing between CVP Servers
Chapter 13
Content Security 363
Advanced CVP Configuration: CVP Chaining and Load Sharing
Combining CVP Chaining and Load Sharing
It is possible to combine CVP chaining and load sharing. Figure 13-11 shows three
CVP servers. Two perform load sharing between themselves, and the load-sharing
group is chained with another CVP server.
It is possible to put a load-sharing group into a CVP chain, but it is not possible to
perform load sharing between chained CVP groups.
Figure 13-11A Chained Load-Sharing CVP Server Group
Configuring CVP Chaining and Load Sharing
1. For each CVP server, define a CVP server object.
To define a CVP server object, right-click in the Servers and OPSEC Application
tree, and select New > OPSEC Application.... In the OPSEC Application Properties
window, General tab, make sure that the selected Server Entities include CVP.
2. Define a CVP Group object. A CVP Group object contains CVP server objects,
and is used in the same way as an OPSEC Application object for a CVP server.
To define a CVP Group object, right-click the Servers and OPSEC Application tree,
and select New > CVP Group.
3. In the CVP Group Properties window, add the CVP servers to the group.
4. Select the Work distribution method: Either Load sharing or Chaining.
5. If you select Load sharing, define the Load sharing method, and the Load sharing
suspend timeout, if any.
6. Create a Resource object. In the Resources tree, right-click and select one of
the following: New > URI..., New > SMTP..., New > FTP..., or New > TCP.... Define
the content security capabilities.
364
Advanced CVP Configuration: CVP Chaining and Load Sharing
7. In the CVP Server field in the CVP tab of the Resource object, select the CVP
Group defined in step 2.
8. In the Security Rule Base, define a rule that uses the Resource.
9. Save and install the security policy.
Chapter 13
Content Security 365
Advanced CVP Configuration: CVP Chaining and Load Sharing
366
14
Chapter
Services with Application
Intelligence
In This Chapter
DCE-RPC
page 368
SSLv3 Service
page 369
SSHv2 Service
page 369
FTP_BASIC Protocol Type
page 369
Domain_UDP Service
page 370
Point-to-Point Tunneling Protocol (PPTP)
page 371
Blocking Visitor Mode (TCPT)
page 373
367
Introduction to Services with Application Intelligence
Introduction to Services with Application
Intelligence
There are a number of TCP services for which VPN-1 can perform content
inspection, in addition to checking port numbers.
Services that support content inspection are those services having a defined
Protocol Type in the TCP Service Properties>Advanced window, either nbsession or
Microsoft-DS together with the configured Resource.
Warning - Do not delete or change the protocol type of the service objects that perform
content inspection. If the service is altered in this way, the content inspection may not work.
DCE-RPC
DCE-RPC (Distributed Computing Environment- Remote Procedure Call) is a
technology that calls a procedure on a remote machine. Unlike other services that
are associated with a specific TCP or UDP port, DCE-RPC uses dynamically
assigned port numbers assigned by the Endpoint Mapper.
DCE-RPC uses the Endpoint Mapper mechanism for the purpose of dynamically
assigning a port number to specific applications. A client that wishes to connect to
a DCE-RPC application typically connects to TCP135 (the default RPC Endpoint
Mapper port) and provides the Endpoint Mapper with a UUID number interface. In
return, the Endpoint Mapper provides the client with a port to which the client can
connect.
SmartView Tracker logs UUID interfaces, making it possible to identify
non-common UUID interfaces. UUID interfaces can be used to enforce security
rules.
368
SSLv3 Service
SSLv3 Service
To prevent security problems associated with earlier versions of SSL, it is possible
to verify that SSL client connections are using version 3 or higher of the SSL
protocol. SSLv3 enforcement is enabled using the ssl_v3 service.
If the ssl_v3 service is used in a rule, and an SSLv2 connection is attempted, the
connection is rejected. Many Internet browsers use SSLv2. To allow their
connections to pass through VPN-1, use the HTTPS service in the Rule Base.
SSHv2 Service
To prevent security problems associated with earlier versions of SSH, it is possible
to verify that SSH connections are using version 2 or higher of the protocol. SSHv2
enforcement is enabled using the ssh_version_2 service.
If the SSHv2 service is used in a rule, SSHv1 connections are dropped.
FTP_BASIC Protocol Type
FTP_BASIC is a new protocol type. This protocol enforces a reduced set of the FTP
security checks performed by the regular FTP protocol type. Using FTP_BASIC
eliminates known connectivity problems with FTP implementations that are not
fully RFC compliant. The following checks are NOT enforced by FTP_BASIC, and
are enforced by the FTP protocol type:
•
Every packet must be terminated with a newline character, so that the PORT
command is not split across packets. This protects against the FTP Bounce
attack.
•
Data connections to or from well-known ports are not allowed, to prevent the
FTP data connection being used to access some other service.
•
Bidirectional traffic on the data connection is not allowed, as it can be used
improperly.
Chapter 14
Services with Application Intelligence 369
Domain_UDP Service
Domain_UDP Service
The Domain_UDP service provides access control for DNS.
370
•
DNS performance when using this service has been improved. Many DNS
connections are for queries which comprise one request and one reply packet.
VPN-1 normally maintains virtual DNS connections for the period of the UDP
timeout. DNS verification speed can be improved by telling VPN-1 to delete the
connection as soon as it receives the reply packet. To do this, change the
property delete_on_reply (false) to true using the Database Tool.
•
DNS logs are more informative. For example, the domain of the device making
a DNS query is now shown in the Information column.
•
DNS verification of EDNS queries is supported. This allows use of BIND. EDNS
headers are allowed if they contain all zeros, other than the field that controls
the packet length (maximum payload size).
Point-to-Point Tunneling Protocol (PPTP)
Point-to-Point Tunneling Protocol (PPTP)
Point-to-Point Tunneling Protocol (PPTP) is a network protocol for creating Virtual
Private Networks (VPNs) over the Internet. It was developed jointly by Microsoft
Corporation and several remote access vendor companies.
PPTP sets up a secure client-to-client connection via a PPTP server. The
connection is made up of TCP/PPTP control connections and the GRE data
connections, GRE being the actual VPN tunnel.
VPN-1 secures PPTP while allowing Hide NAT as well as Static NAT for PPTP
connections. VPN-1 can also enforce compliance to the PPTP protocol. If
enforcement is turned on, PPTP packets are checked for compliance with RFC
2637, including message type, and packet length. In addition, if the PPTP control
connection closes, the GRE tunnel is also closed.
Configuring for PPTP
To configure PPTP:
1. Define an object for the PPTP client that originates the connection, and an
object for the PPTP server (not the destination client).
2. To allow PPTP connections through the VPN-1 gateway, you must define a
PPTP rule in the Security Rule Base using the pptp_tcp service. In the service
column, set either pptp_tcp or Any (by default the pptp_tcp Service object is
set to Match for Any in the Advanced Service Properties).
Table 14-1
Source
Destination
Service
Action
pptp_client
pptp_server
TCP: pptp_tcp
Accept
3. To enforce compliance to the PPTP protocol and allow Hide NAT, turn on
enforcement in SmartDefense Application Intelligence > VPN Protocols > Point to
Point Tunneling Protocol. Static NAT is supported even with the enforcement
turned off. SmartDefense enforcement is turned on by default for new
installations. For upgrades it is turned off.
Chapter 14
Services with Application Intelligence 371
Point-to-Point Tunneling Protocol (PPTP)
4. For gateways of version NG with Application Intelligence (R55) or lower, or if
enforcement is turned off, an additional rule is required to allow the GRE
tunnel:
Table 14-2
Source
Destination
Service
Action
pptp_client
pptp_server
pptp_client
pptp_server
??:GRE
Accept
Advanced Configuration
It is possible to configure strict enforcement of the PPTP protocol using the
pptp_strict_enforcement database property. However, this may cause connectivity
problems because many PPTP applications do not rigorously conform to RFC 2637.
Using the GUIdbedit database tool, go to: Table > Managed Objects > asm >
AdvancedSecurityObject. Open this object, look for the line containing
pptp_strict_enforcement in the value column, and change the value from false
(the default setting) to true.
372
Blocking Visitor Mode (TCPT)
Blocking Visitor Mode (TCPT)
Introduction to TCPT
Visitor mode and the TCP tunneling protocol (TCPT) were developed by Check Point
to allow SecureClient connections from behind any gateway device with a restrictive
outgoing Security Policy. An example of such a Security Policy is one that allows
only HTTP and HTTPS (SSL) outgoing traffic and prevents the various protocols
(such as IKE) required for the secure connections.
Why Block Visitor Mode and Outgoing TCPT?
The VPN-1 administrator can decide to block Visitor mode by implementing a very
restrictive outgoing Security Policy that allows ordinary HTTPS connections and
disallows TCPT connections passing on the same port.
Visitor mode and Incoming TCPT are allowed via the gateway object. Refer to the
Advanced Configuration chapter of the VPN-1 Administration Guide for details.
How VPN-1 Identifies TCPT
VPN-1 performs content inspection in order to identify TCPT packets and reject
them if necessary. It does not merely check the port.
The default port used by TCPT is 443, which is the same port used by SSL. This
can be changed. (Refer to “Changing the Port Used to Block Outgoing TCPT” on
page 374.)
When to Block Outgoing TCPT
Only block TCPT if there is a rule that allows the port used by TCPT, for example,
port 443. If there is no rule that allows the port used by TCPT, then it will be
implicitly blocked, and there is no need explicitly block it.
There are a number of services that perform content inspection, rather than merely
checking port numbers. If you block outgoing TCPT, and there is a rule that allows
a service that uses the same port as TCPT, and that service performs content
inspection, then both TCPT and that service will be blocked. The exception is the
SSLv3 service. A rule that allows SSLv3, permits only SSL version 3 connections,
and rejects TCPT.
Chapter 14
Services with Application Intelligence 373
Blocking Visitor Mode (TCPT)
Services that perform content inspection have a defined Protocol Type in the TCP
Service Properties>Advanced window.
Configuration of Visitor Mode Blocking
Blocking Visitor Mode (Blocking Outgoing TCPT)
To block outgoing TCPT, use the Database Tool on the SmartCenter server to locate
and change the following property for every VPN-1 gateway for which you wish to
block outgoing TCPT:
disable_outgoing_tcpt (false)
Change the value of the property to true.
Changing the Port Used to Block Outgoing TCPT
To change the port used to block TCPT, use the Database Tool and locate the
following global property on the SmartCenter server:
tcpt_outgoing_port (443)
Change the value of the property to the required port number.
374
Web Security
This section describes the VPN-1 Web Content capabilities, as well as the Web
Intelligence feature for VPN-1 that provides high performance attack protection
for web servers and applications.
Chapter
Web Content Protection
15
In This Chapter
Introduction to Web Content Protection
page 378
Web Content Security via the Security Rule Base
page 379
Securing XML Web Services (SOAP)
page 382
Understanding HTTP Sessions, Connections and URLs
page 383
Connectivity Versus Security Considerations for Web Surfers
page 386
Factors Affecting HTTP Security Server Performance
page 388
Configuring Web Content Protection
page 390
377
Introduction to Web Content Protection
Introduction to Web Content Protection
This chapter discusses the following VPN-1 Web Security capabilities:
•
Integrated web security capabilities configured via the Security Rule Base.
These include a number of URL-based protections.
•
The ability to secure XML Web Services (SOAP) on Web servers.
Web Intelligence is a VPN-1 feature that provides high performance attack
protection for Web servers and applications. It provides proactive attack protection
by looking for malicious code and ensuring adherence to protocols and security
best practice. For details about Web Intelligence, refer to “Web Intelligence” on
page 198.
Web Content Security via OPSEC partners allows network virus protection and URL
filtering using best-of-breed Check Point partners. For details, refer to “Content
Security” on page 339.
378
Web Content Security via the Security Rule Base
Web Content Security via the Security Rule
Base
In This Section
What is a URI Resource?
page 379
Filtering URLs, Schemes and Methods by Source and Destination page 379
Basic URL Filtering
page 380
URL Logging
page 380
Java and ActiveX Security
page 381
VPN-1 provides certain web security capabilities that are configured via the
Security Rule Base, rather than Web Intelligence. These include a number of
URL-based protections.
What is a URI Resource?
Web security is implemented via the Security Rule Base by defining a
SmartDashboard object called a URI Resource, and using it in the Security Rule
Base. For a description of Resource objects, refer to “Resources: What They Are
and How to Use Them” on page 352.
URI stands for Uniform Resource Identifier. A URI is more or less identical to the
familiar URL (Uniform Resource Locator).
Filtering URLs, Schemes and Methods by Source
and Destination
It is possible to block URL-based attacks, such as Code Red and Nimda, using a
URI resource. Attacks from and to a specified source and destination can be
blocked. HTTP methods (such as GET and POST) and schemes (such as http, ftp,
and mailto) can also be blocked.
URL patterns are specified using regular expressions. The URL can be broken into
filterable components using the Host, Path and Query parameters that are specified
in the Match tab.
For configuration details, refer to “Blocking URL-based Attacks Using a URI
Resource” on page 390.
Chapter 15
Web Content Protection 379
Web Content Security via the Security Rule Base
Basic URL Filtering
Basic URL Filtering capability is integrated into VPN-1. Use this capability to
restrict user access to as many as 50 URLs, without having to define a separate
resource for each URL.
This method is not recommended for large URL lists, because the list of banned
sites must be defined in a file, and then manually edited and maintained, which is
difficult for a large list of banned sites.
For configuration details, refer to “Configuring Basic URL Filtering” on page 392.
More comprehensive URL Filtering is available using third-party, OPSEC-certified
applications (refer to “Using URL Filtering to Limit Web Surfers” on page 348).
URL Logging
Normally, a logged connection shows the source or destination Web server and
domain (for example http://foo.bar.com).
It is possible to generate extra URL logging information by performing kernel
inspection on the HTTP connection, rather than using a URI Resource, which gives
a less detailed log. This shows in the log the full path and query of the requested
URL, not just the name of the Web server (e.g.,
http://foo.bar.com/products/servlet/Satellite?pagename=1234). Do this by defining
a URI resource and selecting Optimize URL Logging.
For details on configuring the logging of URLs, either by performing kernel
inspection on the HTTP connection or using a URI Resource, refer to “Configuring
URL Logging” on page 391.
380
Web Content Security via the Security Rule Base
Java and ActiveX Security
VPN-1 can protect web surfers by controlling incoming Java and ActiveX code
according to specific conditions, such as host, URL, or authenticated user name.
Java and ActiveX screening capabilities include the following:
•
Stripping ActiveX tags from HTML pages.
•
Stripping Java applet tags from HTML pages.
•
Blocking Java attacks by blocking suspicious back connections.
More comprehensive scanning of Java, ActiveX and other executables can be
accomplished with content security applications from OPSEC-certified vendors.
To screen for Java and ActiveX, you need to define a URI resource and add it to a
Security Rule Base rule. Refer to “Creating a Resource and Using it in the Rule
Base” on page 353.
Chapter 15
Web Content Protection 381
Securing XML Web Services (SOAP)
Securing XML Web Services (SOAP)
VPN-1 provides certain web security capabilities configurable via the Security Rule
Base, rather than Web Intelligence. These include securing SOAP-based XML Web
Services.
XML Web services, using XML Schema and SOAP, facilitate application to
application communication. This is an important emerging communicating protocol
using Internet protocols and standards. This is in contrast to Web pages (using
HTML and DHTML), which are intended for person-to-program communication, and
email and Instant Messaging (using protocols such as SMTP and MIME), which are
also intended ford for person-to-person communication.
The Simple Object Access Protocol (SOAP) provides a way for applications to
communicate with each other over the Internet, independent of platform. SOAP
relies on XML to define the format of the information and then adds the necessary
HTTP headers to send it. XML passes information using commands, called
Methods, that run on the destination computer.
VPN-1 uses a Security server to prevent potential attacks by verifying that the
HTTP, XML, and methods in SOAP requests conform to the RFC. VPN-1 also
ensures that only methods contained in a predefined white-list of acceptable
methods are allowed in a SOAP packet. The manner in which VPN-1 treats SOAP
packets is defined in a URI resource that specifies whether a SOAP packet passing
though the gateway is always accepted, or limited to methods specified in the white
list.
SOAP processing defined in the URI resource is performed only if the HTTP
connection carrying the SOAP message has already been accepted by the rule in
which the URI resource is used. In other words, the connection must match the
rule, and the rule Action cannot be Reject or Drop.
For configuration details, refer to the online help in the URI Resource Properties
SOAP tab.
382
Understanding HTTP Sessions, Connections and URLs
Understanding HTTP Sessions, Connections
and URLs
To understand how to best use VPN-1 Web security and Web Intelligence
protections, it is important to understand some basic terms and concepts regarding
HTTP sessions, HTTP connections, and URLs.
An HTTP session consists of an HTTP request and an HTTP response. In other
words:
HTTP Session = HTTP Request + HTTP Response
Both the HTTP request and the HTTP response have a header section and a body
section.
HTTP Request Example
Header section
The URL is marked in bold for clarity.
GET
http://www.site.com/path/file.html?param1=val1&param2=value2
HTTP/1.1
Host: www.site.com
Range: 1000-2000
Cookie: cookiename=A172653987651987361BDEF
Chapter 15
Web Content Protection 383
Understanding HTTP Sessions, Connections and URLs
Body section
<Some content (usually a filled form which will be submitted)>
HTTP Response Example
Header section
HTTP 200 OK
Content-Encoding: gzip
Content-Type: text/html
Transfer-encoding: chunked
Content-Disposition: http://alternative.url.com
Body section
<Some content (usually an HTML page or a binary file)>
HTTP Connections
HTTP/1.1 encourages the transmission of multiple requests over a single TCP
connection. Each request must still be sent in one contiguous message, and a
server must send responses (on a given connection) in the order that it received the
corresponding requests.
The following is an example of an HTTP request connection:
Request # 1
Header section
Post /Hello/ HTTP/1.1
Host: www.walla.co.il
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT5.0)
Pragma: no-cache
Content-length: 20
Connection: Keep-alive
Request #1 Body
This my example body
Request # 2
Header section
Get /scripts/ HTTP/1.1
Host: www.walla.co.il
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT5.0)
Pragma: no-cache
Content-length: 0
Connection: Keep-alive
384
Understanding HTTP Sessions, Connections and URLs
Understanding URLs
A URL is made up of the Host, Path and Query parameters. In the URL in
Figure 15-1, the Host is http://www.elvis.com, the Path is /alive/qc.html, and the
Query is everything else. VPN-1 and Web Intelligence can filter the URL on these
parameters and decide whether to allow the HTTP request containing a particular
URL.
Figure 15-1Example URL showing Host, Path and Query components
Chapter 15
Web Content Protection 385
Connectivity Versus Security Considerations for Web Surfers
Connectivity Versus Security
Considerations for Web Surfers
To tune connectivity versus security for web surfers, you need to adjust certain
database properties.
Allowing or Restricting Content
Content Disposition Header
The Content-Disposition header in the HTTP Response header suggests to the
client a location where the client should save content (such as a file) carried in the
HTTP response. This location can potentially point to a crucial OS file on the
client. Some clients may take up this suggestion without question and save the
content to that location.
By default, the Content-Disposition header is not allowed. To allow it, from the
SmartDashboard main menu, select Policy> Global Properties, and then
SmartDashboard Customization > Configure. In the Advanced Configuration window,
select FireWall-1 > Web Security > Security. To allow the Content-Disposition header,
check http_allow_content_disposition.
Partial Range Requests
Partial range requests allow the content in an HTTP response to be split over more
than one response. However, content security checks are only completely effective
if the responses are not split in this way.
Adobe Acrobat® uses HTTP ranges to allow pages of Acrobat PDF files to be viewed
as soon as they are downloaded. Not allowing ranges means that the whole file
must be downloaded before it can be viewed. Some download managers also use
HTTP ranges.
Range requests in HTTP requests, and range responses in HTTP responses are not
allowed by default. To allow ranges, from the SmartDashboard main menu, select
Policy> Global Properties, and then SmartDashboard Customization > Configure. In the
Advanced Configuration window, select FireWall-1 > Web Security > Security > Content
Security. To allow range requests, check http_allow_ranges.
386
Connectivity Versus Security Considerations for Web Surfers
Content Compression
Compressing content in HTTP responses is a way of increasing the speed of the
connection. However, content security checks such as HTML weeding and CVP
checking cannot be performed on compressed content.
The Content-Encoding and Content-Type headers in the HTTP response indicate
whether or not the content is compressed, for example: Content-Encoding: gzip,
Content-Type: application/gzip.
The http_disable_content_enc and http_disable_content_type database
properties control whether or not to allow data in the HTTP response to be
compressed. If these properties are false (the default value), compression of
content in an HTTP response is not allowed. Both these properties can be either
true or false. One may be true when the other is false. Each one affects it own
header.
These properties only affect content on which one or more of the following content
security checks are performed: HTML weeding, blocking Java code, CVP, SOAP.
To change the value of this property, in SmartDashboard, edit the Global Properties
in the SmartDashboard Customization > Advanced Configuration page, under Web
Security.
Chapter 15
Web Content Protection 387
Factors Affecting HTTP Security Server Performance
Factors Affecting HTTP Security Server
Performance
On multiple CPU machines, running more than one instance of the HTTP Security
server increases the performance experienced by users. This is because each
Security server uses a different CPU. Run at least one Security server instance for
each CPU (refer to “How To Run Multiple Instances of the HTTP Security Server”
on page 389).
To allow more concurrent connections, it may well be worthwhile to run more than
one Security server, even on a single CPU machine. However, this will increase the
memory usage.
The Number of Simultaneous Security Server
Connections
Each Security server allows up to 1024 file descriptors, which limits the number of
simultaneous connections. In an ordinary connection, packets pass in both
directions through the VPN-1 gateway, as follows:
1. Web client to VPN-1 to Web server (request).
2. Web server to VPN-1 to Web client (response).
512 descriptors are available for use in each direction, so that a total of 512
simultaneous connections are possible.
Where a CVP or UFP server is used, packets in each connection pass through
VPN-1 three times:
1. Web client to VPN-1 to Web server (request).
2. Web server to VPN-1 to CVP/UFP server (response).
3. CVP/UFP server to VPN-1 to Web client (response).
Therefore, the available file descriptors are split three ways, so that a total of 341
simultaneous connections are possible.
388
Factors Affecting HTTP Security Server Performance
How To Run Multiple Instances of the HTTP
Security Server
To run multiple instances of the HTTP Security server:
1. Edit $FWDIR/conf/fwauthd.conf, and include the line
80
in.ahttpd
wait
-2
The last digit on the line is the number of instances of the Security server. In
this example, there are two instances of the HTTP Security server.
2. Restart the VPN-1 gateway (cpstart).
Chapter 15
Web Content Protection 389
Configuring Web Content Protection
Configuring Web Content Protection
In This Section
Blocking URL-based Attacks Using a URI Resource
page 390
Configuring URL Logging
page 391
Configuring Basic URL Filtering
page 392
Blocking URL-based Attacks Using a URI Resource
All URL-based attacks, such as Code Red and Nimda, can be blocked using a URI
resource in SmartDashboard. Each resource can block one attack. For additional
information, refer to “Securing XML Web Services (SOAP)” on page 382.
To block URL-based attacks:
1. Create a new URI Resource, and give it a name (such as Alaska.Web.Protection)
2. In the General tab, select:
•
Use this resource to: Enforce URI capabilities
•
Connection Methods: Normally Transparent and Proxy are selected
•
URI Match Specification Type: Wild Cards
3. Specify the URL pattern, using regular expressions in the Match tab. For
example, to block Code Red, use the following values:
•
Host: *
•
Path: \.ida\?
•
Query: *
4. (Optional) To specify a replacement URL to which to redirect the connection if
the pattern is found, specify a Replacement URI in the Action tab.
5. Associate the Resource with the HTTP Service, and place it in a rule in the
Security Rule Base. Refer to the sample rules shown in Table 15-1.
Table 15-1 Sample URI Resource in a Rule Base
390
No.
Source
Destination
Service
Action
1
Any
Any
http->Alaska.Web.Protection
Drop
2
Any
Any
http
Accept
Configuring Web Content Protection
The Action in Rule 2 is the opposite of the Action in Rule 1. Rule 2 is required
for the Enforce URI Capabilities mode. For the Enhance UFP Performance mode it
is recommended to avoid problems in cases where more than one URI resource
is used in the Rule Base.
Configuring URL Logging
1. Create a URI Resource.
2. Log the URL in the connection in one of the following ways:
•
To log the URLs, including the URL paths and query, by performing kernel
inspection: In the General tab of the URI Resource Properties window, select
Optimize URL Logging.
•
For basic URL logging using the Security server: In the General tab of the
URI Resource Properties window, select Enforce URI Capabilities.
The Exception Track option specifies how to track connections that match
this rule but fail the content security checks. An example of an exception is
a connection with an unsupported scheme or method.
3. Place the URI Resource in a rule with the Action specified as Accept.
4. Select Log in the Track column. This logs the URL of all connections that
match this rule.
For additional information, refer to “URL Logging” on page 380.
Chapter 15
Web Content Protection 391
Configuring Web Content Protection
Configuring Basic URL Filtering
To prevent access to selected forbidden web sites:
1. Specify a list of forbidden sites in a file that lists the site URIs. The URI
specification file is an ASCII file consisting of a list of lines. Each line has the
format:
ip-address /path category
•
ip-address is the IP address of the Web server to be matched. Host names
can be used, but DNS must be enabled and configured on the VPN-1
gateway.
•
/path is optional. Use it to restrict a particular directory in a site.
•
category is an optional parameter that can be any hexadecimal number. It
is not currently used.
Make sure that there is no white space after the category. The last line in the
file must be blank. For example:
192.168.56.78
/games
192.168.25.58
The file should contain no more than 1,000 records.
2. Define a Resource that uses this file.
3. Use this Resource in a rule for all HTTP Traffic.
4. Define the Action as Reject.
For additional information, refer to “Basic URL Filtering” on page 380.
392
Appendices
This section describes how the VPN-1 machine protects itself and the networks
behind it upon activation, and the command line interface.
Appendix
Security Before
VPN-1 Activation
A
In This Appendix
Achieving Security Before VPN-1 Activation
page 396
Boot Security
page 396
The Initial Policy
page 399
Default Filter and Initial Policy Configuration
page 402
395
Achieving Security Before VPN-1 Activation
Achieving Security Before VPN-1 Activation
There are several scenarios in which a computer does not yet have a VPN-1 security
policy installed and is vulnerable. Two features provide security during these
situations: Boot Security, which secures communication during the boot period, and
Initial Policy, which provides security before a security policy is installed for the
first time. As a result, there is no point in time when the computer is left
unprotected.
Boot Security
During the boot process, there is a short period of time (measured in seconds)
between the point when the computer is capable of receiving communication (and
can be attacked) and the point when the security policy is loaded and is enforced.
During this time, VPN-1 Boot Security feature protects both the internal networks
behind the VPN-1 gateway, and the computer itself. Boot Security is provided by
two elements working together:
•
Control of IP Forwarding on boot
•
Default Filter
The Default Filter also provides protection in a scenario where VPN-1 processes are
stopped for maintenance.
Control of IP Forwarding on Boot
For networks protected by a VPN-1 gateway, protection is available at boot by
disabling IP forwarding in the OS kernel. This ensures that there will never be a
time when IP Forwarding is active and no security policy is enforced. This ensures
that networks behind the gateway are safe.
Disabling IP Forwarding protects networks behind the VPN-1 computer, but it does
not protect the VPN-1 computer itself. For this purpose, VPN-1 implements a
Default Filter during the period of vulnerability.
396
Boot Security
The Default Filter
The sequence of actions for a VPN-1 gateway when booting with the Default Filter,
is illustrated in Figure A-1:
•
Computer boots up.
•
Boot security takes effect (Default Filter loads and IP Forwarding is disabled).
•
Interfaces are configured.
•
VPN-1 services start.
The computer is protected as soon as the Default Filter loads.
Figure A-1
How a Default Filter Protects the VPN-1 Gateway Computer
There are five Default Filters:
•
General Filter accepts no inbound communication (this is the default option).
•
Drop Filter accepts no inbound or outbound communication. This filter drops
all communications into and out of the gateway during a period of vulnerability.
Note, however, that if the boot process requires that the gateway communicate
with other hosts, then the Drop Filter should not be used.
•
Default Filter for IPSO allowing SSH incoming communication to support
remote Administration.
•
Default Filter for IPSO allowing HTTPS incoming communication to support
remote Administration.
•
Default Filter for IPSO allowing SSH and HTTPS incoming communication to
support remote Administration.
Appendix A
Security Before VPN-1 Activation 397
Boot Security
The appropriate Default Filter should be selected based on platform and
communication needs. The General Filter is selected by default.
The Default Filter also provides anti-spoofing protection for the VPN-1 gateway. It
ensures that packets whose source are the VPN-1 gateway computer itself have not
come from one of its interfaces.
Using the Default Filter for Maintenance
It is possible to stop VPN-1 processes for maintenance while at the same time
protecting the VPN-1 gateway and the internal network.
During maintenance, the Default Filter allows open connections to the gateway to
remain open, without dropping them.
398
The Initial Policy
The Initial Policy
Until the VPN-1 administrator installs the security policy on the gateway for the
first time, security is enforced by an Initial Policy. The Initial Policy operates by
adding “implied rules” to the Default Filter. These rules forbid most
communication yet allows the communication needed for the installation of the
security policy. The Initial Policy also protects a gateway during Check Point
product upgrades, when a SIC certificate is reset on the gateway, or in the case of
a Check Point product license expiration.
Note - During a Check Point upgrade, a SIC certificate reset, or license expiration, the
Initial Policy overwrites the user-defined policy.
The sequence of actions during boot of the VPN-1 gateway computer until a
security policy is loaded for the first time, is illustrated in Figure A-2.
•
The computer boots up.
•
The Default Filter loads and IP Forwarding is disabled.
•
The Interfaces are configured.
•
VPN-1 services start.
•
The Initial policy is fetched from the local gateway.
•
SmartConsole clients connect or Trust is established, and the security policy is
installed.
Appendix A
Security Before VPN-1 Activation 399
The Initial Policy
Figure A-2
Initial Policy- Until the First Policy Installation
The Initial Policy is enforced until a policy is installed, and is never loaded again.
In subsequent boots, the regular policy is loaded immediately after the Default
Filter.
There are different Initial Policies for standalone and distributed setups. In a
standalone configuration, where the SmartCenter server and VPN-1 gateway are on
the same computer, the Initial Policy allows CPMI communication only. This
permits SmartConsole clients to connect to the SmartCenter server.
400
The Initial Policy
In a distributed configuration, where the Primary SmartCenter server is on one
computer and the VPN-1 gateway is on a different computer, the Initial Policy
allows the following:
•
Primary SmartCenter server computer — allows CPMI communication for
SmartConsole clients.
•
VPN-1 Gateway — allows cpd and fwd communication for SIC communication
(to establish trust) and for Policy installation.
In a distributed configuration, the Initial Policy on the VPN-1 gateway does not
allow CPMI connections. The SmartConsole will not be able to connect to the
SmartCenter server if the SmartConsole must access the SmartCenter server
through a gateway running the Initial Policy.
There is also an Initial Policy for a Secondary SmartCenter server (Management
High Availability). This Initial Policy allows CPMI communication for SmartConsole
clients and allows cpd and fwd communication for SIC communication (to establish
trust) and for Policy installation.
Appendix A
Security Before VPN-1 Activation 401
Default Filter and Initial Policy Configuration
Default Filter and Initial Policy
Configuration
In This Section
Verifying Default Filter or Initial Policy Loading
page 402
Change the Default Filter to a Drop Filter
page 403
User-Defined Default Filter
page 403
Using the Default Filter for Maintenance
page 404
To Unload a Default Filter or an Initial Policy
page 404
If You Cannot Complete Reboot After Installation
page 404
Command Line Reference for Default Filter and Initial Policy
page 405
Verifying Default Filter or Initial Policy Loading
You can verify that the Default Filter and/or Initial Policy are loaded.
To verify loading of the Default Filter or Initial Policy:
1. Boot the system.
2. Before installing another security policy, type the following command:
$FWDIR/bin/fw stat
The command’s output should show that defaultfilter is installed for the
Default Filter status. It should show that InitialPolicy is installed for the
Initial Policy.
402
Default Filter and Initial Policy Configuration
Change the Default Filter to a Drop Filter
For a typical setup there are two Default Filters: defaultfilter.boot and
defaultfilter.drop. They are located in $FWDIR/lib.
To change the Default Filter:
1. Copy over and rename the relevant desired Default Filter Inspect file
(defaultfilter.boot or defaultfilter.drop) to $FWDIR/conf/defaultfilter.pf
2. Compile the Default Filter by running the command:
fw defaultgen
The output will be in $FWDIR/state/default.bin
3. Run fwboot bootconf get_def to print the Default Filter file path.
4. Copy default.bin to the Default Filter file path.
5. If the security policy has not yet been installed, run cpconfig to regenerate the
Initial Policy.
User-Defined Default Filter
For administrators with Inspect knowledge, it is possible to define your own Default
Filter.
To define a Default Filter:
1. Create an Inspect script named defaultfilter.pf in $FWDIR/conf:
Warning - Ensure that the script does not perform any of the following functions:
•
Logging
•
Authentication
•
Encryption
•
Content security
2. Continue from step 2 of “Change the Default Filter to a Drop Filter” on
page 403.”
You must ensure that your security policy does not interfere with the boot process.
Appendix A
Security Before VPN-1 Activation 403
Default Filter and Initial Policy Configuration
Using the Default Filter for Maintenance
It is sometimes necessary to stop VPN-1 processes for maintenance, and it is
impractical to disconnect the VPN-1 gateway computer from the network (for
example, the computer may be at a remote location). The cpstop -fwflag -default
and cpstop -fwflag -proc commands allow VPN-1 processes to be temporarily
stopped for remote maintenance without exposing the computer to attack.
To Unload a Default Filter or an Initial Policy
To unload a Default Filter or an Initial Policy from the kernel, use the same
command that is used for unloading a regular policy. Do this only if you are certain
that you do not need the security provided by the Default Filter or an Initial Policy.
•
To unload the Default Filter locally, run the fw unloadlocal command.
•
To unload an Initial Policy from a remote SmartCenter machine, run the
following command on the SmartCenter server:
fwm unload <hostname>
where hostname is the SIC_name of the gateway.
If You Cannot Complete Reboot After Installation
In certain configurations the Default Filter may prevent the VPN-1 gateway
computer from completing the reboot following installation.
First, examine the Default Filter and verify that the Default Filter allows traffic that
the computer needs in order to boot.
If the boot process cannot complete successfully, remove the Default Filter as
follows:
1. Reboot in single user mode (for UNIX) or Safe Mode With No Networking (for
Windows 2000).
2. Ensure that the Default Filter does not load in future boots. Use the command
fwbootconf bootconf Set_def
3. Reboot.
404
Default Filter and Initial Policy Configuration
Command Line Reference for Default Filter and
Initial Policy
control_bootsec
Enables or disables Boot Security. The command affects both the Default Filter and
the Initial Policy.
Usage
$FWDIR/bin/control_bootsec [-r] [-g]
Table A-1
options control_bootsec
Options
Meaning
-r
Removes boot security
-g
Enables boot security
fwboot bootconf
Use the fwboot bootconf command to configure boot security options. This
command is located in $FWDIR/boot.
Usage
$FWDIR/bin/fwboot bootconf <command> [value]
Table A-2
options fwboot bootconf
Options
Meaning
Get_ipf
Reports whether VPN-1 controls IP Forwarding.
• Returns 1 if IP Forwarding control is enabled
on boot.
• Returns 0 if IP Forwarding is not controlled on
boot.
Appendix A
Security Before VPN-1 Activation 405
Default Filter and Initial Policy Configuration
Table A-2
options fwboot bootconf
Options
Meaning
Set_ipf 0/1
Turns off/on control of IP forwarding for the next
boot.
0 - Turns off
1 - Turns on
Get_def
Returns the full path to the Default Filter that will
be used on boot.
Set_def <filename>
Loads <filename> as the Default Filter in the next
boot. The only safe, and recommended, place to
put the default.bin file is $FWDIR\boot. (The
default.bin filename is a default name.)
Note - Do NOT move these files.
comp_init_policy
Use the comp_init_policy command to generate and load, or to remove, the Initial
Policy.
This command generates the Initial Policy. It ensures that it will be loaded when
the computer is booted, or any other time that a Policy is fetched, for example, at
cpstart, or with the fw fetch localhost command. After running this command,
cpconfig adds an Initial Policy if there is no previous Policy installed.
Usage
$FWDIR/bin/comp_init_policy [-u | -g]
Table A-3
options comp_init_policy
Options
Meaning
-u
Removes the current Initial Policy, and ensures
that it will not be generated in future when
cpconfig is run.
-g
Generates the Initial Policy and ensures that it is
loaded the next time a policy is fetched (at
cpstart, or at next boot, or via the fw fetch
localhost command). After running this
command, cpconfig adds an Initial Policy when
needed.
406
Default Filter and Initial Policy Configuration
The comp_init_policy -g command will only work if there is no previous policy. If
there is a policy, make sure that after removing the policy, you delete the folder
$FWDIR\state\local\FW1\. The $FWDIR/state/local/FW1 folder contains the policy
that will be fetched when fw fetch localhost is run.
The fw fetch localhost command is the command that installs the local policy.
cpstart. comp_init_policy creates the initial policy, but has a safeguard so that
the initial policy will not overwrite a regular user policy (since initial policy is only
used for fresh installations or upgrade). For this reason, you must delete the
$FWDIR\state\local\FW1\ directory if there is a previous policy, otherwise
comp_init_policy will detect that the existing user policy and will not overwrite it.
If you do not delete the previous policy, yet perform the following commands …
comp_init_policy -g + fw fetch localhost
comp_init_policy -g + cpstart
comp_init_policy -g + reboot
… the original policy will still be loaded.
Appendix A
Security Before VPN-1 Activation 407
Default Filter and Initial Policy Configuration
cpstop -fwflag -default and cpstop -fwflag -proc
To stop all VPN-1 processes but leave the Default Filter running, use cpstop -fwflag
-default. To stop all VPN-1 processes but leave the security policy running, use
cpstop -fwflag -proc.
To stop and start all Check Point processes, use
commands should be used with caution.
On Win32 platforms, use the
Point Services.
Services
applet in the
cpstop
and
Control Panel
cpstart.
These
to stop and start Check
Usage
cpstop -fwflag [-default | -proc]
Table A-4
408
Options for fwflag
Options
Meaning
-default
Kills VPN-1 processes (fwd, fwm, vpnd, snmpd etc.).
Logs, kernel traps, resources, and all security server
connections stop working.
The security policy in the kernel is replaced with the
Default Filter.
-proc
Kills VPN-1 processes (fwd, fwm, vpnd etc.). Logs, kernel
traps, resources, and all security server connections stop
working.
The security policy remains loaded in the kernel.
Therefore allow, reject, or drop rules that do not use
resources, but only services, continue to work.
Appendix
Command Line Interface
B
The following command line commands relate to the firewall components of VPN-1.
They are documented in the Command Line Interface (CLI) Administration Guide.
Table B-1
Firewall-related Command Line Interface
Command
Description
comp_init_policy
Generates and loads (or removes) the Initial Policy.
fw
The fw commands are used for working with various
aspects of VPN-1. All fw commands are executed on
the VPN-1 gateway.
fw isp_link
Takes down (or up) one of the redundant ISP links.
fw monitor
A powerful built-in tool to simplify the task of
capturing network packets at multiple capture points
within the firewall chain.
fw tab
Displays kernel table contents and enables you to
change the contents of dynamic tables. Static tables
cannot be changed.
fw stat
Displays the content of state tables on target hosts in
various formats. For each host, the default format
displays the host name and a list of all tables with
their elements.
409
Table B-1
410
Firewall-related Command Line Interface (continued)
Command
Description
fw ver
Displays the VPN-1 major and minor version number
and build number.
sam_alert
Executes VPN-1 SAM (Suspicious Activity
Monitoring) actions according to information received
through standard input. This tool is for executing
SAM actions with the User Defined alerts
mechanism. It is normally run on on the SmartCenter
server.
svr_webupload_config
This utility is used to configure the Eventia Reporter
web upload script.
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permitted provided that this notice is preserved and that due credit is given to the University of Michigan at Ann Arbor. The name of the
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415
416
Index
A
Access Control
definition 31
ActiveX 381
Address Translation Rule
Base 107
Anti-spoofing
and NAT 111
understanding 35
Anti-Virus 227
Anti-Virus Protection
for HTTP 345
for SMTP 354
understanding CVP 345
Application Intelligence 199
Architecture of VPN-1 31
B
Boot Security 396
default filter 396
IP Forwarding 396
boot security
IP Forwarding 396, 405
for any TCP service 360
for HTTP 345
for SMTP
configuring 354
Improving performance 356
Load Sharing 361
D
Default Filter 396
Default Security Policy
verifying that it is
loaded 402
DVMRP (Distance Vector
Multicast Routing Protocol) 37
E
enable_propfind_method 386
End Point Quarantine (EPQ) 42
configuration 52
Error page 200
F
C
CIFS
Configuring protection 331
inspection 329, 330
Code Red 379
Content Security
Connectivity versus
security 386
FTP configuration 337
Performed by Services 373
Cooperative Enforcement 40
configuration 51
CVP
chaining 361
Fingerprint scrambling 192
FTP Commands
limiting using resource 335
fw isp_link 143
FW1_clntauth 84
fwauthd.conf 84
H
H.323 249
configuration 287
Gatekeeper 279
Gateway 279
IP phones 279
NAT Support 280
Protocols 285
routing modes 285
services 286
SmartDefense 284
topologies 280
VoIP Domain 287
Handover 251
VoIP Domain 254
when to enforce 252
Hide NAT 104
HTTP
concurrent connections 204
Sessions 207
http_allow_content_disposition 3
86
http_allow_ranges 386
http_disable_content_enc 387
http_disable_content_type 387
I
IGMP 38
Implied Rules
definition 34
when to edit 46
Instant Messaging 319
Internet Service Provider. See ISP
Redundancy
IP addresses, private and
public 101
IP Forwarding 396
ISP Redundancy
ClusterXL support 146
configuring 150
deployment, choosing 149
deployments 144
dialup support 145
DNS configuration 151
how it works 141
incoming connections 141
link monitoring 141
417
link status 143
modes, choosing 149
modes, understanding 140
NAT, Hide 141, 153
NAT, Static 141, 153
need 138
outgoing connections 141
overview 139
script 143
SmartView Monitor 141
J
Java 381
L
Licensing
Web Intelligence 205
Load agents port property 166
M
Malicious Activity Detection
(MAD) 192
Malicious Code Protector 199
MGCP 249
configuration 309
NAT support 307
securing 303
SmartDefense 305
Monitor-only 187
considerations 202
for all active protections 187
per Web server 187
MSN Messenger
over MSNMS,
configuration 327
over MSNMS, NAT
support 324
over SIP, configuration 325
over SIP, NAT support 323
securing 321
Multicast
addressing 38
configuration 50
protocols 37
418
securing 37
N
Q
QuickUFP. See UFP
enhancing performance
NAT
anti-spoofing 111
arp commands 113
automatic and manual 105
bidirectional 108
definition 102
disabling in VPNs 113
for H.323 280
for SIP 263, 308
Hide address 115
Hide NAT 104
Hide NAT for all internal
networks 106
Hide, planning for 114
IP pools 131
port translation
understanding 111
private and public
addresses 101
Rule Base 107
rule match 107
Static NAT 103
static routes 111
Static, planning for 114
understanding
automatic 109
Network 31
Nimda 379
O
OSPF 37
P
PIM (Protocol-Independent
Multicast) 37
Port scan 193
R
Resource
creating 353
Resources
definition 352
URI resource definition 379
RFC 1918 101
RTP/RTCP 250
Rule Base
basic rules 45
elements 33
using X11 in 46
Rule Base. See Rule Base
S
SCCP 249
configuring 313
securing 311
SmartDefense 312
Security Before VPN-1
Activation 396
Security Policy 32
Security Server
FTP 335
how it works 342
HTTP
CVP 345
CVP performance 346
Security Servers 342
Sequence verifier 180
Services
DNS 370
H.323 286
PPTP 371
SIP 267
SSHv2 369
SSLv3 369
TCPT 373
X11 46
SIP 249
architectural elements 260
logging 257
NAT support 262, 263, 308
Proxy 260
Redirect Server 260, 267,
308
Registrar 260
RFCs 261
services 267
SmartDefense 265
Terminal (IP Phone) 260
topologies 262, 307
Troubleshooting 278
SmartDefense
architecture 183
DoS attack protection 190
H.323 284
Malicious Activity Detection
(MAD) 192
MGCP 305
SCCP 312
sequence verifier 180
SIP 265
updating 210
SmartDefense Profiles
Configuring 214
SOAP 382
Stateful Inspection 31, 199
Static NAT 103
V
version number
displaying 410
Visitor Mode 373
VoIP
DoS protection 255
Handover 251
logging 257
VoIP Domain
Handover 254
VPN-1 version number
displaying 410
W
Web Intelligence
ClusterXL compatibility 199
connectivity
Implications 202
Licensing 205
performance
implications 204
Technologies 199
X
T
X11 service, using in Rule
Base 46
Telephony
threats 248
U
UFP
enhancing performanceconcept 348
enhancing performanceconfiguration 356
for any TCP service 360
rule match behavior 357
URL Filtering
basic 380
using UFP 348
419
420
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