USN-2672-1: NSS vulnerabilities

Publication date

9 July 2015

Overview

Several security issues were fixed in NSS.


Packages

  • 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 machine-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.

Karthikeyan Bhargavan discovered that NSS incorrectly handled state
transitions for the TLS state machine. If a remote attacker were able to
perform a machine-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

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.

Learn more about how to get the fixes.

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

Ubuntu Release Package Version
15.04 vivid libnss3 –  2:3.19.2-0ubuntu15.04.1
14.10 utopic libnss3 –  2:3.19.2-0ubuntu0.14.10.1
14.04 trusty libnss3 –  2:3.19.2-0ubuntu0.14.04.1
12.04 precise libnss3 –  3.19.2-0ubuntu0.12.04.1

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