RHSA-2012:1141 - Security Advisory

Topic

Updated dhcp packages that fix three security issues are now available for
Red Hat Enterprise Linux 6.

The Red Hat Security Response Team 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

The Dynamic Host Configuration Protocol (DHCP) is a protocol that allows
individual devices on an IP network to get their own network configuration
information, including an IP address, a subnet mask, and a broadcast
address.

A denial of service flaw was found in the way the dhcpd daemon handled
zero-length client identifiers. A remote attacker could use this flaw to
send a specially-crafted request to dhcpd, possibly causing it to enter an
infinite loop and consume an excessive amount of CPU time. (CVE-2012-3571)

Two memory leak flaws were found in the dhcpd daemon. A remote attacker
could use these flaws to cause dhcpd to exhaust all available memory by
sending a large number of DHCP requests. (CVE-2012-3954)

Upstream acknowledges Markus Hietava of the Codenomicon CROSS project as
the original reporter of CVE-2012-3571, and Glen Eustace of Massey
University, New Zealand, as the original reporter of CVE-2012-3954.

Users of DHCP should upgrade to these updated packages, which contain
backported patches to correct these issues. After installing this update,
all DHCP servers will be restarted automatically.

Solution

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

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/knowledge/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.3 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.3 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.3 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.3 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.3 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.3 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 842420 - CVE-2012-3571 dhcp: DoS due to error in handling malformed client identifiers
• BZ - 842428 - CVE-2012-3954 dhcp: two memory leaks may result in DoS

CVEs

• CVE-2012-3571
• CVE-2012-3954

References

• https://access.redhat.com/security/updates/classification/#moderate
• http://www.isc.org/software/dhcp/advisories/cve-2012-3571
• http://www.isc.org/software/dhcp/advisories/cve-2012-3954