Airscanner | Mobile Sniffer | The golden age of hacking

The golden age of
War Driving
War Dialing
An overview of modern
wireless networks
CDMA 2000
Evolution of wireless protocols
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
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.
• 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
• 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,
• 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
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)
Wireless Penetration Testing Tools
• Aircrack-ng -
• AirPcap – CACE/Riverbed Technology -
– The ONLY equipment that works in Windows!
• List with Wi-Fi attacks and tools (Wireless attacks, A to Z)
• A bit outdated below!
Understanding WLAN Vulnerabilities
• Vulnerabilities can be broken down into two basic
– 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
Active scanning with old mobile phone
• Barbelo and gpsd under Symbian S60v3(v5)
– (unfortunately bugs)
– (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 '.'
• Other wardriving apps for Windows Mobile 6.x etc.
– AiroMap ( )
• 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
• Hotspotter
• Wicrawl (plugin support)
• Airscanner Mobile Sniffer
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
• Short passphrase (less than 21 characters) is vulnerable to a dictionary attack
Offensive Security: WPA Rainbow Tables, 49 million word dictionary
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
– 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)
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
• Knowing two of key stream, plain-text, and cipher-text lets you easily
compute the third
– 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
• PTW attack
– Builds upon Andreas Klein work which in turn works on FMS/KoreK work
– Fewer data packets/IVs are needed but is limited to only ARP
• For cracking WPA/WPA2 PSK, a dictionary method is preferred
• Elcomsoft Wireless Security Auditor
• Pyrit (Python), backtrack support
• 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
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:
• PMKs are in Windows XP encrypted and decrypted with the DPAPI
CryptProtectData and CryptUnprotectData functions, ex. WZCook (Aircrack-ng)
• The registry/file location of PMKs storage where the Interface GUID represents
the wireless network card
– Windows XP: SOFTWARE\Microsoft\WZCSVC\Parameters\Interfaces\[Interface
– 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)
– 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)
• EAP is an authentication framework, not a specific authentication mechanism
– There are about 40 different EAP methods for authentication
– 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
General EAP authentication
• 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)
– 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
• 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
• (H)MAC = (Hash-based) 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
– 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
• 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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