On Thu, 8 Nov 2001, Dave Dittrich wrote: > ========================================================== > Analysis of SSH crc32 compensation attack detector exploit > ========================================================== I received comments from a number of people about identification of "affected" SSH servers. One such message is here: From markus@openbsd.org Tue Nov 13 18:43:41 2001 Date: Sun, 11 Nov 2001 14:35:31 +0100 Subject: Re: Analysis of SSH crc32 compensation attack detector exploit From: Markus Friedl <markus@openbsd.org> To: Dave Dittrich <dittrich@cac.washington.edu> . . . > are quite visible (remember, this is stock SSH.com 1.2.31 on > Red Hat Linux 6.0 -- syslog signatures for OpenSSH were not obtained > in this analysis): with OpenSSH you would only see the 'fatal:' messages, the 'Connection from' will not be displayed in the default configuration. > One final point. Note the last syslog entry. The successful exploit > causes an authentication attempt to pause while the shell code back door > becomes active. You can connect to the shell and do whatever you > want. Only problem is, the original SSH daemon (at least with SSH.com > 1.2.31) will timeout when the authentication doesn't complete, and the > shell will be terminated. same applies to openssh and probably all ssh-1.x versions. the rules are simpler: 1) protocol 2 only all SSH-2.0-* are not affected, since no protocol v1 is iisnvolved. 2) protocol 1 und 2 support since SSH-1.99-* supports both protocol versions, it gets more difficult. for the commercial server, you never know the version of the server that will be called for the fallback, you have to assume that all SSH-1.99-[23]* are affected, and SSH-1.99-OpenSSH[-_].x.y are affected for versions x.y < 2.3 3) protocol 1 only SSH-1.5-OpenSSH[-_].x.y is affected versions x.y < 2.3 and the commercial versions. SSH-1.5-1.2.2[456789] SSH-1.5-1.2.3[01] so: [updates to table removed] -markus The analysis has been updated to reflect this, and the script modified somewhat. The most recent version can be found at: http://staff.washington.edu/dittrich/misc/ssh-analysis.txt -- Dave Dittrich Computing & Communications dittrich@cac.washington.edu University Computing Services http://staff.washington.edu/dittrich University of Washington PGP key http://staff.washington.edu/dittrich/pgpkey.txt Fingerprint FE 97 0C 57 08 43 F3 EB 49 A1 0C D0 8E 0C D0 BE C8 38 CC B5
