USN-1007-1: NSS vulnerabilities

20 October 2010

An attacker could view sensitive information in an unlikely circumstance.



  • nspr - NetScape Portable Runtime Library
  • nss - Network Security Service libraries


Richard Moore discovered that NSS would sometimes incorrectly match an SSL
certificate which had a Common Name that used a wildcard followed by a partial
IP address. While it is very unlikely that a Certificate Authority would issue
such a certificate, if an attacker were able to perform a man-in-the-middle
attack, this flaw could be exploited to view sensitive information.

Nelson Bolyard discovered a weakness in the Diffie-Hellman Ephemeral mode
(DHE) key exchange implementation which allowed servers to use a too small
key length. (CVE-2010-3173)

Update instructions

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

Ubuntu 9.10
Ubuntu 9.04
Ubuntu 8.04
Ubuntu 10.10
Ubuntu 10.04

After a standard system update you need to restart any applications that
use NSS, such as Firefox, Thunderbird or Evolution, to make all the
necessary changes. This update also includes updated NSPR packages to work
with the new NSS.