RHSA-2008:0181 - Security Advisory

Topic

Updated krb5 packages that fix multiple security issues 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 through use of symmetric encryption
and a trusted third party, the KDC.

A flaw was found in the way the MIT Kerberos Authentication Service and Key
Distribution Center server (krb5kdc) handled Kerberos v4 protocol packets.
An unauthenticated remote attacker could use this flaw to crash the
krb5kdc daemon, disclose portions of its memory, or possibly execute
arbitrary code using malformed or truncated Kerberos v4 protocol
requests. (CVE-2008-0062, CVE-2008-0063)

This issue only affected krb5kdc with Kerberos v4 protocol compatibility
enabled, which is the default setting on Red Hat Enterprise Linux 4.
Kerberos v4 protocol support can be disabled by adding "v4_mode=none"
(without the quotes) to the "[kdcdefaults]" section of
/var/kerberos/krb5kdc/kdc.conf.

A flaw was found in the RPC library used by the MIT Kerberos kadmind
server. An unauthenticated remote attacker could use this flaw to crash
kadmind. This issue only affected systems with certain resource limits
configured and did not affect systems using default resource limits used by
Red Hat Enterprise Linux 2.1 or 3. (CVE-2008-0948)

Red Hat would like to thank MIT for reporting these issues.

All krb5 users are advised to update to these erratum packages which
contain backported fixes to correct these issues.

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/FAQ_58_10188

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 - 432620 - CVE-2008-0062 krb5: uninitialized pointer use in krb5kdc
• BZ - 432621 - CVE-2008-0063 krb5: possible leak of sensitive data from krb5kdc using krb4 request
• BZ - 435087 - CVE-2008-0948 krb5: incorrect handling of high-numbered file descriptors in RPC library

CVEs

• CVE-2008-0948
• CVE-2008-0062
• CVE-2008-0063

References

• http://www.redhat.com/security/updates/classification/#critical