dhclient, dhcp security update

CentOS Errata and Security Advisory CESA-2012:1141

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.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2012-August/080947.html

Affected packages:
dhclient
dhcp
dhcp-common
dhcp-devel

Upstream details at:
https://access.redhat.com/errata/RHSA-2012:1141