RHSA-2016:0684 - Security Advisory

Topic

An update for nss and nspr is now available for Red Hat Enterprise Linux 5.

Red Hat Product Security has rated this update as having a security impact of
Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a
detailed severity rating, is available for each vulnerability from the CVE
link(s) in the References section.

Description

Network Security Services (NSS) is a set of libraries designed to support the
cross-platform development of security-enabled client and server applications.
Netscape Portable Runtime (NSPR) provides platform independence for non-GUI
operating system facilities.

The following packages have been upgraded to a newer upstream version: nss
3.21.0, nspr 4.11.0. (BZ#1297944, BZ#1297943)

Security Fix(es):

• A use-after-free flaw was found in the way NSS handled DHE (Diffie-Hellman key

exchange) and ECDHE (Elliptic Curve Diffie-Hellman key exchange) handshake
messages. A remote attacker could send a specially crafted handshake message
that, when parsed by an application linked against NSS, would cause that
application to crash or, under certain special conditions, execute arbitrary
code using the permissions of the user running the application. (CVE-2016-1978)

• A use-after-free flaw was found in the way NSS processed certain DER

(Distinguished Encoding Rules) encoded cryptographic keys. An attacker could use
this flaw to create a specially crafted DER encoded certificate which, when
parsed by an application compiled against the NSS library, could cause that
application to crash, or execute arbitrary code using the permissions of the
user running the application. (CVE-2016-1979)

Red Hat would like to thank the Mozilla project for reporting these issues.
Upstream acknowledges Eric Rescorla as the original reporter of CVE-2016-1978;
and Tim Taubert as the original reporter of CVE-2016-1979.

Solution

For details on how to apply this update, which includes the changes described in
this advisory, refer to:

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

After installing this update, applications using NSS or NSPR (for example,
Firefox) must be restarted for this update to take effect.

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 - 1297943 - Rebase RHEL 5.11.z to NSPR 4.11 in preparation for Firefox 45.
• BZ - 1297944 - Rebase RHEL 5.11.z to NSS 3.21 in preparation for Firefox 45.
• BZ - 1315202 - CVE-2016-1979 nss: Use-after-free during processing of DER encoded keys in NSS (MFSA 2016-36)
• BZ - 1315565 - CVE-2016-1978 nss: Use-after-free in NSS during SSL connections in low memory (MFSA 2016-15)

CVEs

• CVE-2016-1979
• CVE-2016-1978

References

• https://access.redhat.com/security/updates/classification/#moderate