Ubuntu 6.06 LTS / 8.04 LTS / 8.10 / 9.04 : gnutls12, gnutls13, gnutls26 vulnerabilities (USN-809-1)

high Nessus Plugin ID 40656


The remote Ubuntu host is missing one or more security-related patches.


Moxie Marlinspike and Dan Kaminsky independently discovered that GnuTLS did not properly handle certificates with NULL characters in the certificate name. An attacker could exploit this to perform a man in the middle attack to view sensitive information or alter encrypted communications. (CVE-2009-2730)

Dan Kaminsky discovered GnuTLS would still accept certificates with MD2 hash signatures. As a result, an attacker could potentially create a malicious trusted certificate to impersonate another site. This issue only affected Ubuntu 6.06 LTS and Ubuntu 8.10. (CVE-2009-2409)

USN-678-1 fixed a vulnerability and USN-678-2 a regression in GnuTLS.
The upstream patches introduced a regression when validating certain certificate chains that would report valid certificates as untrusted.
This update fixes the problem, and only affected Ubuntu 6.06 LTS and Ubuntu 8.10 (Ubuntu 8.04 LTS and 9.04 were fixed at an earlier date).
In an effort to maintain a strong security stance and address all known regressions, this update deprecates X.509 validation chains using MD2 and MD5 signatures. To accomodate sites which must still use a deprected RSA-MD5 certificate, GnuTLS has been updated to stop looking when it has found a trusted intermediary certificate. This new handling of intermediary certificates is in accordance with other SSL implementations.

Martin von Gagern discovered that GnuTLS did not properly verify certificate chains when the last certificate in the chain was self-signed. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to view sensitive information. (CVE-2008-4989).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.


Update the affected packages.

See Also


Plugin Details

Severity: High

ID: 40656

File Name: ubuntu_USN-809-1.nasl

Version: 1.16

Type: local

Agent: unix

Published: 8/20/2009

Updated: 1/19/2021

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent

Risk Information


Risk Factor: High

Score: 7.4


Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P

Temporal Vector: E:U/RL:OF/RC:C

Vulnerability Information

CPE: p-cpe:/a:canonical:ubuntu_linux:gnutls-bin, p-cpe:/a:canonical:ubuntu_linux:gnutls-doc, p-cpe:/a:canonical:ubuntu_linux:guile-gnutls, p-cpe:/a:canonical:ubuntu_linux:libgnutls-dev, p-cpe:/a:canonical:ubuntu_linux:libgnutls12, p-cpe:/a:canonical:ubuntu_linux:libgnutls12-dbg, p-cpe:/a:canonical:ubuntu_linux:libgnutls13, p-cpe:/a:canonical:ubuntu_linux:libgnutls13-dbg, p-cpe:/a:canonical:ubuntu_linux:libgnutls26, p-cpe:/a:canonical:ubuntu_linux:libgnutls26-dbg, p-cpe:/a:canonical:ubuntu_linux:libgnutlsxx13, cpe:/o:canonical:ubuntu_linux:6.06:-:lts, cpe:/o:canonical:ubuntu_linux:8.04:-:lts, cpe:/o:canonical:ubuntu_linux:8.10, cpe:/o:canonical:ubuntu_linux:9.04

Required KB Items: Host/cpu, Host/Ubuntu, Host/Ubuntu/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 8/19/2009

Reference Information

CVE: CVE-2008-4989, CVE-2009-2409, CVE-2009-2730

BID: 35952

USN: 809-1

CWE: 255, 310