José Selvi - Historia de un CryptoFAIL [rootedvlc4]
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En ocasiones, los usuarios y empresas tenemos excesiva confianza en que nuestros proveedores de software y servicios cumplen con todos los requisitos lógicos de seguridad. Por desgracia, en ocasiones no es así, y es habitual encontrarte con herramientas comerciales vulnerables que pueden poner en riesgo nuestra seguridad. En esta charla, comentaremos algunos conceptos básicos sobre el uso de criptografía, y mostraremos un ejemplo de como se encontró una vulnerabilidad por mal uso de cripografía en un software que pretendía ser un reemplazo para una conocida herramienta de gestión remota de equipos de usuario.
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José Selvi - Historia de un CryptoFAIL [rootedvlc4]
- 1. A CRYPTO-FAIL STORY RootedCON Valencia September 2017
- 2. 2 Jose Selvi (@Jose Selvi) +12 years in the infosec industry Principal Penetration Tester & Security Researcher SANS Institute Community Instructor GIAC Security Expert (GSE) Blogger (sometimes): http://www.pentester.es $ WHOIS JSELVI
- 3. 3 I DID NOT MAKE A FULL VULNERABILITY RESEARCH
- 4. 4 THIS IS NOT A CRYPTO TRAINING
- 5. 5
- 6. 6
- 7. 7 TESTING CRYPTO IN 30 MINUTES test1@test.com : 123456 -> 5A 8D 7D B4 DB B4 05 E9 AB CC 2D 46 AD AD 21 7F test1@test.com : 123456 -> 5A 8D 7D B4 DB B4 05 E9 AB CC 2D 46 AD AD 21 7F REUSE SALT, REUSE IV test1@test.com : 123456 -> 5A 8D 7D B4 DB B4 05 E9 AB CC 2D 46 AD AD 21 7F test1@test.com : 000000 -> 2E C7 7C 2A 19 6E 02 2B AA 68 7E F0 61 67 51 B0 test1@test.com : 123456 -> 5A 8D 7D B4 DB B4 05 E9 AB CC 2D 46 AD AD 21 7F test2@test.com : 123456 -> 7B 49 CF 4D E4 32 1E 77 93 21 1A B5 74 8B 44 DA BASED ON EMAIL & PASSWORD BLOCK CIPHER (REVERSIBLE) ENCRYPTION B6 78 78 BD F5 72 FC BE 04 8B D5 33 44 98 7B 02 23 97 F8 B5 BD 63 3F 6D F8 AB 13 64 76 DD 37 BE 5A 8D 7D B4 DB B4 05 E9 AB CC 2D 46 AD AD 21 7F
- 9. 9 NO EXPLOITATION, NO FUN POTENTIALLY EXPLOITABLE WE PRESUME THAT WITH ENOUGH EFFORT IT COULD BE EXPLOITED
- 10. 10 QUICK LOOK AT THE BINARY $ rabin2 -i server.exe | grep -i crypt ordinal=001 plt=0x005c80c4 bind=NONE type=FUNC name=CRYPTUI.dll_CryptUIDlgViewCertificateW ordinal=001 plt=0x005c8098 bind=NONE type=FUNC name=CRYPT32.dll_CertEnumCertificatesInStore ordinal=002 plt=0x005c809c bind=NONE type=FUNC name=CRYPT32.dll_CertCloseStore ordinal=003 plt=0x005c80a0 bind=NONE type=FUNC name=CRYPT32.dll_CertFreeCertificateContext ordinal=004 plt=0x005c80a4 bind=NONE type=FUNC name=CRYPT32.dll_CertGetCertificateContextProperty ordinal=005 plt=0x005c80a8 bind=NONE type=FUNC name=CRYPT32.dll_CertDuplicateCertificateContext ordinal=006 plt=0x005c80ac bind=NONE type=FUNC name=CRYPT32.dll_CertGetEnhancedKeyUsage ordinal=007 plt=0x005c80b0 bind=NONE type=FUNC name=CRYPT32.dll_CertGetNameStringW ordinal=008 plt=0x005c80b4 bind=NONE type=FUNC name=CRYPT32.dll_CertOpenStore ordinal=009 plt=0x005c80b8 bind=NONE type=FUNC name=CRYPT32.dll_CryptProtectData ordinal=010 plt=0x005c80bc bind=NONE type=FUNC name=CRYPT32.dll_CryptUnprotectData $ rabin2 -zz server.exe | grep -i crypt vaddr=0x00626ff6 paddr=0x002257f6 ordinal=21488 sz=27 len=26 section=.rdata type=ascii string=CryptUIDlgViewCertificateW vaddr=0x00627012 paddr=0x00225812 ordinal=21489 sz=12 len=11 section=.rdata type=ascii string=CRYPTUI.dll vaddr=0x0062755a paddr=0x00225d5a ordinal=21555 sz=17 len=16 section=.rdata type=ascii string=CryptProtectData vaddr=0x0062756e paddr=0x00225d6e ordinal=21556 sz=19 len=18 section=.rdata type=ascii string=CryptUnprotectData vaddr=0x00627582 paddr=0x00225d82 ordinal=21557 sz=12 len=11 section=.rdata type=ascii string=CRYPT32.dll vaddr=0x0062f6e0 paddr=0x0022dae0 ordinal=22387 sz=40 len=39 section=.data type=ascii string=.?AU? $Deleter@UCryptData@@P6AHPAU1@@Z@@ vaddr=0x0062f710 paddr=0x0022db10 ordinal=22388 sz=30 len=29 section=.data type=ascii string=.?AV? $TPointer@UCryptData@@@@ vaddr=0x0062f738 paddr=0x0022db38 ordinal=22389 sz=34 len=33 section=.data type=ascii string=.?AV? $TAutoFreeObj@UCryptData@@@@
- 11. 11
- 12. 12 HASHING ALGORITHMS static void reset(uint32_t digest[], std::string &buffer, uint64_t &transforms) { /* SHA1 initialization constants */ digest[0] = 0x67452301; digest[1] = 0xefcdab89; digest[2] = 0x98badcfe; digest[3] = 0x10325476; digest[4] = 0xc3d2e1f0; /* Reset counters */ buffer = ""; transforms = 0; }
- 14. 14 BLOCK CIPHERS
- 15. 15
- 16. 16
- 17. 17 AES has 10 rounds for 128-bit keys, 12 rounds for 192-bit keys, and 14 rounds for 256-bit keys.
- 18. 18
- 19. 19
- 20. 20
- 21. 21
- 22. 22 CRACKING THE “HASH” $ ./crack my@email.com 52796b User: my@email.com Password: test123456
- 23. 23 RESULT
- 24. 24 DO NOT USE ECB MODE NEVER EVER
- 25. 25 $ echo Testing1234 | openssl enc -aes-128-ecb -K 1234 -iv 1 | hexd 0000000 8d 47 5c 5f bb 1b 1c 0a 79 ca e5 45 6a 8f c4 58 $ echo Testing1234 | openssl enc -aes-128-ecb -K 1234 -iv 2 | hexd 0000000 8d 47 5c 5f bb 1b 1c 0a 79 ca e5 45 6a 8f c4 58 $ echo Testing1234 | openssl enc -aes-128-cbc -K 1234 -iv 0001 | hexdump 0000000 d5 1e 92 d4 ce 72 dc ab 6d e9 c0 b6 bb 39 de f7 $ echo Testing1234 | openssl enc -aes-128-cbc -K 1234 -iv 0002 | hexdump 0000000 1b 28 1f e3 10 fa 69 14 8b 80 e2 64 97 2e 93 d0
- 27. 27 ALWAYS USE DIFFERENT IVs ON EACH MESSAGE
- 28. 28 REUSING IVs ON AES $ echo Testing1234 | openssl enc -aes-128-cbc -K 1234 -iv 1 | hexdump 0000000 d5 1e 92 d4 ce 72 dc ab 6d e9 c0 b6 bb 39 de f7 $ echo Testing1234 | openssl enc -aes-128-cbc -K 1234 -iv 1 | hexdump 0000000 d5 1e 92 d4 ce 72 dc ab 6d e9 c0 b6 bb 39 de f7 $ echo Testing1234 | openssl enc -aes-128-cbc -K 1234 -iv 1 | hexdump 0000000 d5 1e 92 d4 ce 72 dc ab 6d e9 c0 b6 bb 39 de f7 $ echo Testing1234 | openssl enc -aes-128-cbc -K 1234 -iv 1 | hexdump 0000000 d5 1e 92 d4 ce 72 dc ab 6d e9 c0 b6 bb 39 de f7 $ echo Testing1234 | openssl enc -aes-128-cbc -K 1234 -iv 1 | hexdump 0000000 d5 1e 92 d4 ce 72 dc ab 6d e9 c0 b6 bb 39 de f7
- 29. 29 REUSING IVs ON STREAM CIPHERS W E L C O M E T O T H I S 12 34 56 78 9A BC DE F0 12 34 56 78 9A BC DE F0 H I D D E N M E S S A G E ! . 12 34 56 78 9A BC DE F0 12 34 56 78 9A BC DE F0 (M1 ⊕ KEY) ⊕ (M2 ⊕ KEY) M1 ⊕ M2
- 30. 30 DO NOT USE REVERSIBLE ENCRYPTION FOR PASSWORDS
- 31. Credentials Storage 31 AUTHENTICATION & HASHING pass1234 Client Side Server Side XYZW XYZW
- 32. Code Credentials Storage 32 SALT & PEPPER pass1234 Client Side Server Side SALT$XYZW SALT$XYZW PEPPER PEPPERSALT
- 33. 33 PASSWORD SPECIFIC HASHING: PBKDF2, BCRYPT, SCRYPT, …
- 34. 34 SERIOUSLY, DO NOT KEEP SECRETS AT CLIENT SIDE
- 35. XYZWABCD Random Token Generator Token Storage 35 RANDOM TOKENS Client Side Server Side XYZWABCD
- 36. JSON Token Generator XYZWABCD Token Storage 36 JSON WEB TOKENS (JWT) Client Side Server Side Certification Authority CA
- 37. www.prosegur.comwww.prosegur.com THANKS A LOT! ANY QUESTIONS? jose.selvi@prosegur.com jselvi@pentester.es @JoseSelvi