USN-810-3: NSS regression

2 September 2009

nss regression

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

  • Ubuntu 9.04
  • Ubuntu 8.10
  • Ubuntu 8.04 LTS

Software Description

  • nss


USN-810-1 fixed vulnerabilities in NSS. Jozsef Kadlecsik noticed that the new libraries on amd64 did not correctly set stack memory flags, and caused applications using NSS (e.g. Firefox) to have an executable stack. This reduced the effectiveness of some defensive security protections. This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Moxie Marlinspike discovered that NSS did not properly handle regular expressions in certificate names. A remote attacker could create a specially crafted certificate to cause a denial of service (via application crash) or execute arbitrary code as the user invoking the program. (CVE-2009-2404)

Moxie Marlinspike and Dan Kaminsky independently discovered that NSS 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-2009-2408)

Dan Kaminsky discovered NSS would still accept certificates with MD2 hash signatures. As a result, an attacker could potentially create a malicious trusted certificate to impersonate another site. (CVE-2009-2409)

Update instructions

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

Ubuntu 9.04
libnss3-1d -
Ubuntu 8.10
libnss3-1d -
Ubuntu 8.04 LTS
libnss3-1d -

To update your system, please follow these instructions:

After a standard system upgrade you need to restart any applications that use NSS, such as Firefox, to effect the necessary changes.