RHSA-2015:1664 - Security Advisory

Topic

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.

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.

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

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

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

CVEs

• CVE-2015-2721
• CVE-2015-2730

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://www.mozilla.org/security/announce/2015/mfsa2015-64.html
• https://www.mozilla.org/security/announce/2015/mfsa2015-71.html