Several security issues were fixed in NSS.
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)
9 July 2015
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in NSS.
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.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
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.
Vulmon