Airscanner | Mobile Sniffer | The golden age of hacking

The golden age of
hacking
War Driving
War Dialing
An overview of modern
wireless networks
3G
4G
W-CDMA
CDMA 2000
WiMAX
LTE
http://en.wikipedia.org/wiki/4G
Evolution of wireless protocols
http://en.wikipedia.org/wiki/IEEE_802.11ac
OSI model according to IEEE 802.11
• The MAC layer provides a set of services e.g. data transfer, association, reassociation, authentication, privacy, and power management that control
the communications between the wireless stations (STA) and access points
(AP) over a shared medium
• 802.11a/g/n/ac uses OFDM (Orthogonal Frequency-Division Multiplexing)
– Same as in ADSL, VDSL, WiMAX, DVB-T(2), LTE etc...
Extensible Authentication Protocol
EAP
OFDM
Worlds largests hotspots 
• War Driving is the act of moving around a specific area, mapping the
population of wireless access points for statistical purposes
• Laptop setup (could also be a PDA)
– A laptop computer
– A wireless network interface
card (NIC) Card
– An external antenna
– A pigtail to connect the external
antenna to the wireless NIC
– A handheld global positioning
system (GPS) unit
– A GPS data cable
– A War Driving software program
– A cigarette lighter or AC adapter power inverter
• Mobile phone with built in GPS and Wi-Fi
– A War Driving software program, no additional equipment needed!
NIC:s, software etc.
http://www.aircrack-ng.org/doku.php?id=compatibility_drivers
• ESSID (Extended Service Set IDentifier)
– Default: Netgear, Linksys, Belkin, Dlink etc.
• BSSID (Basic Service Set IDentifier)
– MAC address of the AP or client
• Before purchasing a wireless card, you should determine the software and
configuration you plan to use
Gigabyte GN-WB01GS
• Chipset software support
– Atheros, Ralink, RTL818*...
– AirPcap (Windows)
• External antenna?
• Connectors?
Ralink RT73
USB works in VMware!
• Support for rfmon/monitor mode (passive/sniff scan with no AP connection)
– rfmon/monitor mode = promiscuous mode ++ (listen on all WLANs)
– Linux ok
– Windows - usually not
RF (Radio Frequency)
• There are 11 channels used in the U.S. and Canada and 13
channels in Europe on the 2.4 GHz spectrum starting with
Channel 1 at 2.412 GHz and incremented by 0.005 GHz (5
MHz) for each channel
• The Relationship of Wavelength and Cycle with a Radio Wave
km/s
• λ = wavelength in meters
• f = frequency in kilohertz
• For 2.45 GHz - 802.11g
RF Terminology 1
• Radio Signal
– RF wave that has been changed to carry some information,
modulated
• Direct Sequence Spread Spectrum (DSSS), Frequency Hopping
Spread, Spectrum (FHSS), Orthogonal Frequency-Division
Multiplexing (OFDM) etc.
• Noise
– Is the measurement of how many stray RF signals are in
the same frequency area
• Noise Floor
– The level of background RF noise, typical noise floor for
802.11b/g signals is usually about -90 dBm to -100 dBm
• RSSI (Received Signal Strength Indication)
– 0 to RSSI_Max (-100 to -50 dBm) , or just Signal Strength
RF Terminology 2
• Decibels (radio waves)
– Magnitude of power decrease over distance
– Ratio of power levels is used – Bel, dB (1/10 Bel)
• The equation for decibels is:
– where p = the power reference
• Usually for wireless it (p) is to one milliWatt (mW) (1/1000 Watt)
• A radio transmitting a 0 dBm signal sends with p = 1mW, 10 dBm
sends 10 mW and 20 dBm sends 100 mW ... 30 dBm sends with?
-20 dBm sends with?
• It is typical to se negative numbers to show decibels of a received
signal which represent a gradual loss, or attenuation of a signal
• Positive numbers indicate a signal addition or gain
RF Terminology 3
• Signal strength - typical AP
– 100 – 500 mW (20 - 27 dBm)
• Signal strength - typical Client Adapter
– 30 – 200 mW (13 - 23 dBm)
• Estimated loss
– Plasterboard (gipsskiva) at 4 dBm, brick wall at 8 dBm, and concrete wall at 10 - 15 dBm
• S - N = SNR (Signal-to-Noise Ratio)
– S is Signal Strength in dBm and N is Noise in dBm
– Ex: Wi-Fi HW shows a signal of -82dBm and a noise floor of -96dBm which gives SNR =
14dBm (-82dBm - -96dBm)
• Multipath (reflections)
– Can be good and bad (out of sync gives interference)
– MIMO (Multiple Input Multiple Output) - interference as advantage
• Diversity
– Equipment got more than one antenna - uses the one with best signal
minimize multi-path fading
RF Terminology 4
• Impedance (usually 50 ohm)
– Is the electrical load on an antenna circuit, wrong ohm (Ω)
can give high attenuation (dämpning) which kills the signal
– Cables and other components
• Polarization
– Vertical is most
common
Passive antenna types
• Gain in
– dBi (isotropic), dBd (dipole)
– dBd = dBi - 2,15 dB
• Omnidirectional antennas
– Typical 4 - 5 dBi
• Directional antennas
– Grid, typical 21 - 24 dBi
– Panel
– Pringles 
• Yagi
– Typical 10 - 17 dBi
• Non-distorting the waveform
– RF Amplifiers
– Attenuators (reduce power)
http://www.educypedia.be/electronics/rfwlan.htm
Wireless Penetration Testing Tools
• Aircrack-ng - http://www.aircrack-ng.org
• AirPcap – CACE/Riverbed Technology - http://www.cacetech.com/
– The ONLY equipment that works in Windows!
• List with Wi-Fi attacks and tools (Wireless attacks, A to Z)
• http://searchsecurity.techtarget.com/generic/0,295582,sid14_gci1167611,00.html
• http://wirelessdefence.org
2011: http://www.tech-faq.com/wi-fi-software-tools.html
• A bit outdated below!
Understanding WLAN Vulnerabilities
• Vulnerabilities can be broken down into two basic
types
– Vulnerabilities due to poor configuration
– Vulnerabilities due to poor encryption
• Attacks usually use one of these three techniques
– Active scanning
– Passive scanning
– Forcing deauthentication
• Pen-testing WLAN
– Target Identification
• ESSID : Name of the WLAN
• BSSID : MAC address of AP or STA
• Probing with ESSID ”Any” makes most of the APs answer with
their ESSID
• AP:s sends beacon packets every 100 ms with ESSID in clear text
Active scanning (any probe) with Netstumbler
• Superseeded by inSSIDer
– http://www.inssider.com/
Active scanning with old mobile phone
• Barbelo and gpsd under Symbian S60v3(v5)
– http://darkircop.org/barbelo/ (unfortunately bugs)
– http://wiki.nomi.cz/gpsd:start (also turn your phone into BT GPS)
• Kisgearth (Perl script - Kismet XML > KML)
– More than 1 AP in Wi-Fi network log
– å, ä, ö and comma (',') must be converted to US standard '.'
– http://mytty.org/kisgearth/
• Other wardriving apps for Windows Mobile 6.x etc.
– AiroMap (http://blogs.wefrag.com/divide/airosuite/ )
– http://www.wardrive.net/wardriving/tools/
• View KML with Google Earth
View in Google Earth
Active scanning with
Android phone
• Android apps (there is a lot!)
• Most support KML, export etc.
• Wardrive, Wigle WiFi, WiFi Scanner
• Scout, G-MoN, WlanPollution
• Antennas (Cell-ID)
• Penetrate (Crack)
• ...
Passive scanning (rfmon/monitor mode)
• Handheld - Wellenreiter II
– http://www.vanille-media.de/site/index.php/projects/wellenreiter-ii/
• Hotspotter
– http://www.wirelessdefence.org/Contents/hotspotter.htm
• Wicrawl (plugin support)
– http://midnightresearch.com/projects/wicrawl/
• Airscanner Mobile Sniffer
– http://www.airscanner.com/
Packet Sniffer
Passive scanning with
• Also used to capture data when forcing deauthentication
Cain and CACE AirPcap USB dongle
• a
War Driving Defenses
• Set non informative ESSID in AP and an unique name
• Set AP to ignore probe requests that do not contain ESSID and omit ESSID in
beacon packets
• Set AP to filter out MAC-addresses that are unknown
– Mac MakeUp (Windows)
– ifconfig [if] hw ether [mac address] (Unix)
• Wired Equivalent Privacy (WEP)
– Protocol is broken – not recommended to use
– FMS (Fluhrer, Mantin, and Shamir)/KoreK attack method - 2001
– PTW (Pyshkin, Tews, Weinmann) attack method - 2007
• WiFi Protected Access (WPA)
– WPA implements a subset of 802.11i (WPA2) but uses RC4 instead of AES cipher
– WPA/WPA2-PSK
• Short passphrase (less than 21 characters) is vulnerable to a dictionary attack
http://seclists.org/isn/2003/Nov/0021.html
Offensive Security: WPA Rainbow Tables, 49 million word dictionary
– http://www.offensive-security.com/wpa-tables/
WEP (Wired Equivalent Privacy)
• IVs (initialization vectors) used
with stream cipher RC4
– IV produce a unique stream independent
from other streams produced by the
same encryption key
• RC4 uses the key to initialize a state
machine via Key Scheduling Algorithm
(KSA)
– Then continuously modifies the state and
generates a new byte of the key-stream
from the new state
• RC4 XOR-encrypts one byte at a time
with the key-stream output from
Pseudo Random Generation
Algorithm (PRGA)
– http://en.wikipedia.org/wiki/RC4
– http://en.wikipedia.org/wiki/Wired_Equiv
alent_Privacy
WEP key reuse
• Many packets contain well known fields at well known locations
– E.g. header fields in IP and ARP etc.
• RC4 64 bit seed is created by concatenating a 40 bit shared secret (10 hex
characters) with a 24 bit initialization vector (IV)
• A family of 2^24 keys for each shared secret
• Keys are cycled for each packet
– Frames can be lost and stream ciphers do not deal with missing bits, so the
stream must be reset with each packet
– Therefore, a new IV is sent in the clear with each packet
• IV is only 24 bits, the time to repeat IV’s (and thus keys) with high
probability is very short
– 50% probability of getting some IV reuse after using 4096 IV’s
– 99% likely that you get IV re-use after 12430 frames or 1 or 2 seconds of
operation at 11 Mbps
Aircrack-ng
http://www.aircrack-ng.org/doku.php?id=aircrack-ng
• Knowing two of key stream, plain-text, and cipher-text lets you easily
compute the third
XOR
– Reusing a key value is a really, really bad idea.
A well known fact for RC4
• FMS/KoreK chopchop attack method
– When enough IVs are captured incorporate various statistical attacks to
discover the WEP key and use these in combination with brute forcing
– http://en.wikipedia.org/wiki/Fluhrer,_Mantin,_and_Shamir_attack
– http://www.aircrack-ng.org/doku.php?id=korek_chopchop
• PTW attack
– Builds upon Andreas Klein work which in turn works on FMS/KoreK work
• http://eprint.iacr.org/2007/120
– Fewer data packets/IVs are needed but is limited to only ARP
– http://www.cdc.informatik.tu-darmstadt.de/aircrack-ptw/
• For cracking WPA/WPA2 PSK, a dictionary method is preferred
WPA/WPA2-PSK
• Elcomsoft Wireless Security Auditor
• Pyrit (Python), backtrack support
– http://code.google.com/p/pyrit/
• Only wordlist or hash chain attack make sense!
• Algorithm – the PMK (Pair-wise Master Key)
may be pre-computed
PTK is captured
with aircrack-ng
424
Possible offline extraction of PMKs
• Pre-Shared Key (PSK): 8-63 printable ASCII characters (keyspace 96)
• Note! You may not need the PSK, try use the PMK hash directly in config?
• PMK = 32 bytes (256 bits), PBKDF2 = HMAC-SHA1, iterated 4096 times
– Generate a PMK hash: http://www.wireshark.org/tools/wpa-psk.html
• PMKs are in Windows XP encrypted and decrypted with the DPAPI
CryptProtectData and CryptUnprotectData functions, ex. WZCook (Aircrack-ng)
– http://msdn.microsoft.com/en-us/library/ms706987%28VS.85%29.aspx
• The registry/file location of PMKs storage where the Interface GUID represents
the wireless network card
– Windows XP: SOFTWARE\Microsoft\WZCSVC\Parameters\Interfaces\[Interface
GUID]
– Windows Vista/7: stored in the file system in a .xml file (keyMaterial element), under
C:\ProgramData\Microsoft\Wlansvc\Profiles\Interfaces\[Interface GUID]
• Starting from Windows 7, Microsoft changed the encryption and hashing
algorithms that are used by the Windows Data Protection (DPAPI) system
• In Linux the PMK is usually stored in some wpa_supplicant config file
802.11i architecture
• WPA2 = 802.11i also called RSN(Robust Security Network)
• The 802.11i architecture contains the following components
– 802.1X for authentication (entailing the use of EAP and an authentication server)
• http://en.wikipedia.org/wiki/802.1x
– AES-based CCMP (Counter Mode with Cipher Block Chaining Message Authentication Code
Protocol), to provide confidentiality, integrity and origin authentication
• Replaces TKIP (Temporal Key Integrity Protocol)
– http://en.wikipedia.org/wiki/IEEE_802.11i
• EAP is an authentication framework, not a specific authentication mechanism
– There are about 40 different EAP methods for authentication
• EAP-MD5, EAP-OTP, EAP-GTC, EAP-TLS, EAP-IKEv2, EAP-SIM, EAP-AKA, PEAP, LEAP,
EAP-TTLS… EAP-PSK
– EAP (Extensible Authentication Protocol) methods and messages provide
authentication and a secure PMK (Pair-wise Master Key) between STA and AP
– If EAP is embedded in 802.1x it is called EAPOL (EAP Over LANs)
• The PMK/PTK is used for the wireless encryption session which uses TKIP or CCMP
• http://en.wikipedia.org/wiki/Extensible_Authentication_Protocol
General EAP authentication
http://www.netcraftsmen.net/welcher/papers/dot1x.html
• Encapsulation of EAP Over LANs
– 802.1X EAPOL
– Layer 2 wrapper to transport
EAP information
• EAPOL start is only used if the
supplicant init the exchange
• Green dotted lines shows RADIUS
(AS) messages
• EAP-OTP (One Time Password)
• EAP-PSK = OTP
– If passphrase is 256 bit, PMK =
passphrase, else
– PMK = PBKDF2(passphrase, ssid,
ssidLength, 4096, 256)
– Hashed 4096 times
802.11i Encryption key distribution
• The earlier 802.1x EAP exchange has provided the shared secret key PMK
(Pair-wise Master Key) Note! If it is WPA2-PSK we already know it.
– This key is however designed to last the entire session and should be exposed as little as
possible
• Therefore the four-way handshake is used to establish another key called
the PTK (Pair-wise Transient Key)
– The PTK is generated by concatenating the following attributes: PMK, AP nonce
(ANonce), STA nonce (SNonce), AP MAC address and STA MAC address
– The product is then put through a cryptographic
hash function
– The handshake also yields the GTK (Group Temporal
Key), used to decrypt multicast and broadcast traffic
– Nonce stands for: number or bit string used only once
– MIC = Message Integrity Code
– All the messages are sent as EAPOL-Key frames
– http://en.wikipedia.org/wiki/IEEE_802.11i
MAC
• (H)MAC = (Hash-based) Message Authentication Code
– http://en.wikipedia.org/wiki/HMAC
– http://en.wikipedia.org/wiki/Message_authentication_code
MIC and the hierarchy of keys
• The KCK (Key Confirmation Key) is used for computing the MIC (Message
Integrity code)
• If computed MIC is equal to eavesdropped MIC we can calculate the PSK/MK
MIC = hmac_sha/md5(key, 16, data);
RADIUS, VPN and defense
• Remote Autenthication Dial-In User Service (RADIUS)
–
–
–
–
–
–
AAA (Autehentication, Authorization and Accounting)
Centralized client/server approach
Uses a shared secret that never is sent over the net
Flexible authentication with PAP, CHAP, LDAP etc.
Uses UDP port 1812
FreeRADIUS http://www.freeradius.org
• VPN
– PPTP and L2TP
– IPsec
– OpenVPN (SSL/TLS based)
• IDS (Intrusion Detection System)
• Physical defense (Faraday cage)
or turn down transmit power
War Dialing
• Looking for modems in all the right places
– Remote access lines
– Often weak protection
• Automated dialers
– Feed with recon data
• TCH-Scan 2.0
– Full featured
– http://freeworld.thc.org/welcome/
• If inside you really are inside!
• Defenses
– Modem policy
– Dial out only
– Find the modems before the attacker
WiFi Definitions 1
WiFi Definitions 2
WiFi Definitions 3
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