Ubuntu 12.04 LTS / 14.04 LTS / 14.10 / 15.04 : nss vulnerabilities (USN-2672-1)
Medium Nessus Plugin ID 84666
SynopsisThe remote Ubuntu host is missing a security-related patch.
DescriptionKarthikeyan 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.
Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
SolutionUpdate the affected libnss3 package.