USN-355-1: openssh vulnerabilities

Ubuntu Security Notice USN-355-1

2nd 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

Details

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 version:

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: https://wiki.ubuntu.com/Security/Upgrades.

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

References

CVE-2006-4924, CVE-2006-5051