============================================================================
Ubuntu Security Notice USN-2672-1
July 09, 2015

nss vulnerabilities
============================================================================

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

- Ubuntu 15.04
- Ubuntu 14.10
- Ubuntu 14.04 LTS
- Ubuntu 12.04 LTS

Summary:

Several security issues were fixed in NSS.

Software Description:
- nss: Network Security Service library

Details:

Karthikeyan Bhargavan discovered that NSS incorrectly handled state
transitions for the TLS state machine. If a remote attacker were able to
perform a man-in-the-middle attack, this flaw could be exploited to skip
the ServerKeyExchange message and remove the forward-secrecy property.
(CVE-2015-2721)

Watson Ladd discovered that NSS incorrectly handled Elliptical Curve
Cryptography (ECC) multiplication. A remote attacker could possibly use
this issue to spoof ECDSA signatures. (CVE-2015-2730)

As a security improvement, this update modifies NSS behaviour to reject DH
key sizes below 768 bits, preventing a possible downgrade attack.

This update also refreshes the NSS package to version 3.19.2 which includes
the latest CA certificate bundle.

Update instructions:

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

Ubuntu 15.04:
  libnss3                         2:3.19.2-0ubuntu15.04.1

Ubuntu 14.10:
  libnss3                         2:3.19.2-0ubuntu0.14.10.1

Ubuntu 14.04 LTS:
  libnss3                         2:3.19.2-0ubuntu0.14.04.1

Ubuntu 12.04 LTS:
  libnss3                         3.19.2-0ubuntu0.12.04.1

This update uses a new upstream release, which includes additional bug
fixes. After a standard system update you need to restart any applications
that use NSS, such as Evolution and Chromium, to make all the necessary
changes.

References:
  http://www.ubuntu.com/usn/usn-2672-1
  CVE-2015-2721, CVE-2015-2730

Package Information:
  https://launchpad.net/ubuntu/+source/nss/2:3.19.2-0ubuntu15.04.1
  https://launchpad.net/ubuntu/+source/nss/2:3.19.2-0ubuntu0.14.10.1
  https://launchpad.net/ubuntu/+source/nss/2:3.19.2-0ubuntu0.14.04.1
  https://launchpad.net/ubuntu/+source/nss/3.19.2-0ubuntu0.12.04.1