USN-355-1: openssh vulnerabilities

02 October 2006

openssh vulnerabilities



Tavis Ormandy discovered that the SSH daemon did not properly handle
authentication packets with duplicated blocks. By sending specially
crafted packets, a remote attacker could exploit this to cause the ssh
daemon to drain all available CPU resources until the login grace time
expired. (CVE-2006-4924)

Mark Dowd discovered a race condition in the server's signal handling.
A remote attacker could exploit this to crash the server.

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 6.06
  • openssh-server - 1:4.2p1-7ubuntu3.1
Ubuntu 5.10
  • openssh-server - 1:4.1p1-7ubuntu4.2
Ubuntu 5.04
  • openssh-server - 1:3.9p1-1ubuntu2.3

In general, a standard system upgrade is sufficient to effect the
necessary changes.