Didier Stevens

Sunday 21 October 2018

Release: Python Tool Templates

Filed under: Announcement,My Software — Didier Stevens @ 0:00

I’m releasing the templates for Python tools I shared and used during my BruCON and Hack.lu 2018 workshops.

There’s a template for text files and one for binary files.

python-templates_V0_0_1.zip (https)
MD5: 99E9D87681470F1BAE020B68F2853F49
SHA256: 2CA24AD6928FA2FE2DE894FEFBD1B41238B723D46ADED4064D26374A805BA1C4

Wednesday 10 October 2018

KEIHash: Fingerprinting SSH

Filed under: Encryption,My Software,Networking — Didier Stevens @ 0:00

keihash.py is a program to parse pcap files and calculate the KEIHash of SSH connections.

The KEIHash is the MD5 hash of the Key Exchange Init (KEI) data (strings). For obvious reasons, I could not call this an SSH fingerprint. This is inspired by JA3 SSL fingerprinting.

It can be used to profile SSH clients and servers. For example, the hash for the latest version of PuTTY (SSH-2.0-PuTTY_Release_0.70) is 1c5eaa56f3e4569385ae5f82a54715ee.

This is the MD5 hash of:

240-curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,rsa2048-sha256,rsa1024-sha1,diffie-hellman-group1-sha1;87-ssh-rsa,ssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-dss;189-aes256-ctr,aes256-cbc,rijndael-cbc@lysator.liu.se,aes192-ctr,aes192-cbc,aes128-ctr,aes128-cbc,chacha20-poly1305@openssh.com,blowfish-ctr,blowfish-cbc,3des-ctr,3des-cbc,arcfour256,arcfour128;189-aes256-ctr,aes256-cbc,rijndael-cbc@lysator.liu.se,aes192-ctr,aes192-cbc,aes128-ctr,aes128-cbc,chacha20-poly1305@openssh.com,blowfish-ctr,blowfish-cbc,3des-ctr,3des-cbc,arcfour256,arcfour128;155-hmac-sha2-256,hmac-sha1,hmac-sha1-96,hmac-md5,hmac-sha2-256-etm@openssh.com,hmac-sha1-etm@openssh.com,hmac-sha1-96-etm@openssh.com,hmac-md5-etm@openssh.com;155-hmac-sha2-256,hmac-sha1,hmac-sha1-96,hmac-md5,hmac-sha2-256-etm@openssh.com,hmac-sha1-etm@openssh.com,hmac-sha1-96-etm@openssh.com,hmac-md5-etm@openssh.com;9-none,zlib;9-none,zlib;0-;0-

These are all the strings found in the Key Exchange Init packet, prefixed by their length and concatenated with separator ;.

With this, I’ve been able to identify SSH clients with spoofed banners attempting to connect to my servers.

keihash_V0_0_1.zip (https)
MD5: 674D019A739679D9659D2D512A60BDD8
SHA256: DB7471F1253E3AEA6BFD0BA38C154AF3E1D1967F13980AC3F42BB61BBB750490

Monday 1 October 2018

Title: Overview of Content Published in September

Filed under: Announcement — Didier Stevens @ 0:00

Here is an overview of content I published in September:

Blog posts:

YouTube videos:

Videoblog posts:

SANS ISC Diary entries:

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