USN-355-1: openssh vulnerabilities

2 October 2006

openssh vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 6.06 LTS
  • Ubuntu 5.10
  • Ubuntu 5.04

Software Description


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. (CVE-2006-5051)

Update instructions

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

Ubuntu 6.06 LTS
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

To update your system, please follow these instructions:

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