RHSA-2009:0410 - Security Advisory

Topic

Updated krb5 packages that fix a security issue are now available for Red
Hat Enterprise Linux 2.1 and 3.

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

Description

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).

An input validation flaw was found in the ASN.1 (Abstract Syntax Notation
One) decoder used by MIT Kerberos. A remote attacker could use this flaw to
crash a network service using the MIT Kerberos library, such as kadmind or
krb5kdc, by causing it to dereference or free an uninitialized pointer or,
possibly, execute arbitrary code with the privileges of the user running
the service. (CVE-2009-0846)

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

Solution

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

Affected Products

• Red Hat Enterprise Linux Server 3 x86_64
• Red Hat Enterprise Linux Server 3 ia64
• Red Hat Enterprise Linux Server 3 i386
• Red Hat Enterprise Linux Server 2 ia64
• Red Hat Enterprise Linux Server 2 i386
• Red Hat Enterprise Linux Workstation 3 x86_64
• Red Hat Enterprise Linux Workstation 3 ia64
• Red Hat Enterprise Linux Workstation 3 i386
• Red Hat Enterprise Linux Workstation 2 ia64
• Red Hat Enterprise Linux Workstation 2 i386
• Red Hat Enterprise Linux Desktop 3 x86_64
• Red Hat Enterprise Linux Desktop 3 i386
• Red Hat Enterprise Linux for IBM z Systems 3 s390x
• Red Hat Enterprise Linux for IBM z Systems 3 s390
• Red Hat Enterprise Linux for Power, big endian 3 ppc

Fixes

• BZ - 491036 - CVE-2009-0846 krb5: ASN.1 decoder can free uninitialized pointer when decoding an invalid encoding (MITKRB5-SA-2009-002)

CVEs

• CVE-2009-0846

References

• http://www.redhat.com/security/updates/classification/#critical
• http://web.mit.edu/kerberos/advisories/MITKRB5-SA-2009-002.txt