Moderate: ntp security update

Updated ntp packages to correct a security issue are now available for Red
Hat Enterprise Linux 4 and 5.

This update has been rated as having moderate security impact by the Red
Hat Security Response Team.

The Network Time Protocol (NTP) is used to synchronize a computer's time
with a referenced time source.

A flaw was discovered in the way the ntpd daemon checked the return value
of the OpenSSL EVP_VerifyFinal function. On systems using NTPv4
authentication, this could lead to an incorrect verification of
cryptographic signatures, allowing time-spoofing attacks. (CVE-2009-0021)

Note: This issue only affects systems that have enabled NTP authentication.
By default, NTP authentication is not enabled.

All ntp users are advised to upgrade to the updated packages, which contain
a backported patch to resolve this issue. After installing the update, the
ntpd daemon will restart automatically.

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

This update is available via Red Hat Network. Details on how to use
the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/docs/DOC-11259

476807 - CVE-2009-0021 ntp incorrectly checks for malformed signatures

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-0021
http://www.redhat.com/security/updates/classification/#moderate