Critical: krb5 security update

Updated krb5 packages that fix multiple security issues are now available
for Red Hat Enterprise Linux 3, 4, and 5, and Red Hat Enterprise Linux 4.7,
5.2, and 5.3 Extended Update Support.

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

Kerberos is a network authentication system which allows clients and
servers to authenticate to each other using symmetric encryption and a
trusted third party, the Key Distribution Center (KDC).

Multiple integer underflow flaws, leading to heap-based corruption, were
found in the way the MIT Kerberos Key Distribution Center (KDC) decrypted
ciphertexts encrypted with the Advanced Encryption Standard (AES) and
ARCFOUR (RC4) encryption algorithms. If a remote KDC client were able to
provide a specially-crafted AES- or RC4-encrypted ciphertext or texts, it
could potentially lead to either a denial of service of the central KDC
(KDC crash or abort upon processing the crafted ciphertext), or arbitrary
code execution with the privileges of the KDC (i.e., root privileges).
(CVE-2009-4212)

All krb5 users should upgrade to these updated packages, which contain a
backported patch to correct these issues. All running services using the
MIT Kerberos libraries must be restarted for the update to take effect.

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

545015 - CVE-2009-4212 krb: KDC integer overflows in AES and RC4 decryption routines (MITKRB5-SA-2009-004)

https://www.redhat.com/security/data/cve/CVE-2009-4212.html
http://www.redhat.com/security/updates/classification/#critical
http://web.mit.edu/kerberos/advisories/MITKRB5-SA-2009-004.txt