4.3 - RHSA-2015:1664

Problem Description:

Updated nss packages that fix two security issues, several bugs, and add various enhancements are now available for Red Hat Enterprise Linux 5.

Red Hat Product Security has rated this update as having Moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

2. Relevant releases/architectures:

RHEL Desktop Workstation (v. 5 client) - i386, x86_64 Red Hat Enterprise Linux (v. 5 server) - i386, ia64, ppc, s390x, x86_64 Red Hat Enterprise Linux Desktop (v. 5 client) - i386, x86_64

3. Description:

Network Security Services (NSS) is a set of libraries designed to support cross-platform development of security-enabled client and server applications.

It was found that NSS permitted skipping of the ServerKeyExchange packet during a handshake involving ECDHE (Elliptic Curve Diffie-Hellman key Exchange). A remote attacker could use this flaw to bypass the forward-secrecy of a TLS/SSL connection. (CVE-2015-2721)

A flaw was found in the way NSS verified certain ECDSA (Elliptic Curve Digital Signature Algorithm) signatures. Under certain conditions, an attacker could use this flaw to conduct signature forgery attacks. (CVE-2015-2730)

Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Karthikeyan Bhargavan as the original reporter of CVE-2015-2721, and Watson Ladd as the original reporter of CVE-2015-2730.

The nss packages have been upgraded to upstream version 3.19.1, which provides a number of bug fixes and enhancements over the previous version.

All nss users are advised to upgrade to these updated packages, which correct these issues.

4. Solution:

Before applying this update, make sure all previously released errata relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

5. Bugs fixed (https://bugzilla.redhat.com/):

1236954 - CVE-2015-2730 NSS: ECDSA signature validation fails to handle some signatures correctly (MFSA 2015-64) 1236967 - CVE-2015-2721 NSS: incorrectly permited skipping of ServerKeyExchange (MFSA 2015-71)