Ubuntu 15.04 USN-2672-1 Critical: NSS Man-in-the-Middle Threat

ubuntu

July 9, 2015

Several security issues were fixed in NSS.

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.

Topics Covered

security advisory update critical ubuntu man-in-the-middle tls nss

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.