USN-810-3: NSS regression

02 September 2009

NSS regression



  • 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.

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.

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
Ubuntu 8.10
Ubuntu 8.04

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