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WPA, what else?

WPA, what else?. Thomas d’Otreppe de Bouvette Aircrack-ng. UNAM, Mexico City November 27-28, 2008. Agenda. WEP WPA – How does it work? WPA – Practice Location, location, location Cracking the key Bruteforce WPA - Tools Airbase-ng Tkiptun-ng Airolib-ng Practical stuff. 2. WEP.

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WPA, what else?

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  1. WPA, what else? Thomas d’Otreppe de Bouvette Aircrack-ng UNAM, Mexico City November 27-28, 2008

  2. Agenda • WEP • WPA – How does it work? • WPA – Practice • Location, location, location • Cracking the key • Bruteforce • WPA - Tools • Airbase-ng • Tkiptun-ng • Airolib-ng • Practical stuff 2

  3. WEP • It was fun • A few new attacks were created • Caffe Latte • Cfrag • PTW2: Now needs less packets needed by PTW to crack a key • WEP Cloaking™ is now dead too 3

  4. WEP • WPA – How does it work? • WPA – Practice • Location, location, location • Cracking the key • Bruteforce • WPA - Tools • Airbase-ng • Tkiptun-ng • Airolib-ng • Practical stuff 4

  5. WPA • More and more networks use WPA • WPA is a hot topic these days: • CUDA • New attack and tool: tkiptun-ng 5

  6. WPA • 802.11i group launched when flaws were found in WEP • 2 link-layer protocols: • TKIP (WPA1): Draft 3 of 802.11i group (backward compatible with legacy hardware). • CCMP (WPA2): final 802.11i standard • 2 authentication methods: • Personal: PSK • Enterprise: MGT 6

  7. WPA-PSK – How does it work? 7

  8. WPA-PSK – 4 way handshake 9

  9. WPA-PSK – PTK Construction

  10. WPA-PSK – PMK Construction

  11. WEP • WPA – How does it work? • WPA – Practice • Location, location, location • Cracking the key • Bruteforce • WPA - Tools • Airbase-ng • Tkiptun-ng • Airolib-ng • Practical stuff 16

  12. WPA – Location • Need all packets from the 4 way handshake => hear AP and Client • In fact, aircrack-ng can work with less than 4 packets • If too far, won’t get everything

  13. WPA – Location (2)

  14. WPA – Location (3)

  15. WPA – Cracking the key • Processing Unit • CPU • GPU (CUDA and AMD Stream) • Method: • Wordlist • Bruteforce • « Rainbow » tables

  16. WPA - CUDA • Cracking with your nVidia • Much faster than with a CPU (10-100x): • Intel P4 3.2Ghz: ~150 keys/sec • AMD Turion 64 X2 TL-60 (2Ghz): ~230 keys/sec • Nvidia 280GTX: ~11000 keys/sec • A few tools exists • Commercial • Open source: pyrit • Planned in aircrack-ng (AMD Stream too) 21

  17. WPA - Pyrit cracking speed 22

  18. WPA - Bruteforce • Let’s calculate how much time it will take to crack a simple passphrase with alphanumerical values (upper and lower case). • Smallest WPA passphrase: 8 characters (max 63). 23

  19. WPA - Bruteforce (2) • 8 characters passphrase • 62 possibilities per character: [A-Z][a-z][0-9] • Using a 280GTX (11000keys/sec) • 62^8 = 218 340 105 584 896 possible keys • 218340105584896/11000k/s= 19 849 100 508 sec • 19849100508 sec = 5 513 639 hours • 5513639 hours = 229 735 days • 229735 days = 630 years 24

  20. 630 years for a 8 char WPA key • A bit too long for a simple passphrase. • For a 12 characters passphrase, bruteforce will take 9 309 091 680 years. • Dictionnary attack and John The ripper are still the best solution. 25

  21. WEP • WPA – How does it work? • WPA – Practice • Location, location, location • Cracking the key • Bruteforce • WPA - Tools • Airbase-ng • Tkiptun-ng • Airolib-ng • Practical stuff 26

  22. Airbase-ng “Airbase-ng is multi-purpose tool aimed at attacking clients as opposed to the Access Point (AP) itself.” Features: • Soft AP/Ad hoc • Karma • Encrypt/Decrypt packets • Capture WPA handshake from a client. • Filtering to avoid disturbing nearby networks 27

  23. Airbase-ng (2) • Turn any monitor-mode capable card into an AP • Default mode: Karma • Karmetasploit = airbase-ng + metasploit 28

  24. Fun with airbase-ng • Karma • airbase-ng rausb0 • Soft AP: • airbase-ng –y –e myAP –c 6 rausb0 • ifconfig at0 up 192.168.0.254 • ping/ssh/… it from the client • Script to manipulate packets: • airbase-ng –Y both rausb0 • ./test/replay.py at1 29

  25. Fun with airbase-ng (2) • WPA Handshake capture: airbase-ng -z 2 -W 1 –y -c 6 -e home rausb0 • Location problem solved ;), you just need the client:

  26. Tkiptun-ng • Exaggerated in the news, only a few frames can be sent • Work in Progress: • Basic documentation written • Not fully working yet 31

  27. Tkiptun-ng (2) • WPA TKIP + QoS (802.11e) • Decrypt packets from the AP • Modified chopchop • Breaks the MIC key • Save plaintext + keystream 32

  28. Airolib-ng • Create pre-computed WPA hash tables to be used with aircrack-ng • Uses a sqlite database • Import/Export: • Import passphrases/essid lists • Cowpatty tables (genpmk) • Pyrit can exports its hash tables to airolib-ng format • Speed (once precomputed): • EEE 701 (900Mhz, SD Card): ~9700keys/sec • AMD Turion 64 X2 TL-60 (2Ghz, HDD 7200rpm): ~55500 keys/sec (~30000 keys/sec virtualized).

  29. Conclusion • Questions? • Practical stuff • WPA Cracking • Fun: Aigraph-ng

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