Debian Security Advisory

DSA-1212-1 openssh -- Denial of service

Date Reported:
15 Nov 2006
Affected Packages:
Security database references:
In the Debian bugtracking system: Bug 392428.
In the Bugtraq database (at SecurityFocus): BugTraq ID 20216, BugTraq ID 20241.
In Mitre's CVE dictionary: CVE-2006-4924, CVE-2006-5051.
More information:

Two denial of service problems have been found in the OpenSSH server. The Common Vulnerabilities and Exposures project identifies the following vulnerabilities:

  • CVE-2006-4924

    The sshd support for ssh protocol version 1 does not properly handle duplicate incoming blocks. This could allow a remote attacker to cause sshd to consume significant CPU resources leading to a denial of service.

  • CVE-2006-5051

    A signal handler race condition could potentially allow a remote attacker to crash sshd and could theoretically lead to the ability to execute arbitrary code.

For the stable distribution (sarge), these problems have been fixed in version 1:3.8.1p1-8.sarge.6.

For the unstable and testing distributions, these problems have been fixed in version 1:4.3p2-4.

We recommend that you upgrade your openssh package.

Fixed in:

Debian GNU/Linux 3.1 (stable)

Intel IA-32:
Intel IA-64:
Motorola 680x0:
Big endian MIPS:
Little endian MIPS:
IBM S/390:
Sun Sparc:

MD5 checksums of the listed files are available in the original advisory.