Topic

Updated krb5 packages that fix multiple security issues and several bugs
are now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having Moderate security
impact. Common Vulnerability Scoring System (CVSS) base scores, which give
detailed severity ratings, are available for each vulnerability from the
CVE links in the References section.

Description

Kerberos is a networked authentication system which allows clients and
servers to authenticate to each other with the help of a trusted third
party, the Kerberos KDC.

It was found that if a KDC served multiple realms, certain requests could
cause the setup_server_realm() function to dereference a NULL pointer.
A remote, unauthenticated attacker could use this flaw to crash the KDC
using a specially crafted request. (CVE-2013-1418, CVE-2013-6800)

A NULL pointer dereference flaw was found in the MIT Kerberos SPNEGO
acceptor for continuation tokens. A remote, unauthenticated attacker could
use this flaw to crash a GSSAPI-enabled server application. (CVE-2014-4344)

A buffer overflow was found in the KADM5 administration server (kadmind)
when it was used with an LDAP back end for the KDC database. A remote,
authenticated attacker could potentially use this flaw to execute arbitrary
code on the system running kadmind. (CVE-2014-4345)

Two buffer over-read flaws were found in the way MIT Kerberos handled
certain requests. A remote, unauthenticated attacker who is able to inject
packets into a client or server application's GSSAPI session could use
either of these flaws to crash the application. (CVE-2014-4341,
CVE-2014-4342)

A double-free flaw was found in the MIT Kerberos SPNEGO initiators.
An attacker able to spoof packets to appear as though they are from an
GSSAPI acceptor could use this flaw to crash a client application that uses
MIT Kerberos. (CVE-2014-4343)

These updated krb5 packages also include several bug fixes. Space precludes
documenting all of these changes in this advisory. Users are directed to
the Red Hat Enterprise Linux 6.6 Technical Notes, linked to in the
References section, for information on the most significant of these
changes.

All krb5 users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues.

Solution

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

This update is available via the Red Hat Network. Details on how to use the
Red Hat Network to apply this update are available at
https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 1001961 - Wrong obsoletes in krb5-pkinit-openssl
• BZ - 1009389 - service krb5kdc start unable to get default realm
• BZ - 1026942 - CVE-2013-1418 krb5: multi-realm KDC null dereference leads to crash
• BZ - 1031499 - CVE-2013-6800 krb5: KDC remote DoS (NULL pointer dereference and daemon crash)
• BZ - 1059730 - Kerberos does not handle incorrect Active Directory DNS SRV entries correctly
• BZ - 1087068 - 0006526: GSS api stopped working properly after krb5 update
• BZ - 1113652 - trusted domain logins cannot find KDC for requested realm
• BZ - 1116180 - CVE-2014-4341 krb5: denial of service flaws when handling padding length longer than the plaintext
• BZ - 1120581 - CVE-2014-4342 krb5: denial of service flaws when handling RFC 1964 tokens
• BZ - 1121876 - CVE-2014-4343 krb5: double-free flaw in SPNEGO initiators
• BZ - 1121877 - CVE-2014-4344 krb5: NULL pointer dereference flaw in SPNEGO acceptor for continuation tokens
• BZ - 1128157 - CVE-2014-4345 krb5: buffer overrun in kadmind with LDAP backend (MITKRB5-SA-2014-001)

CVEs

• CVE-2013-1418
• CVE-2014-4341
• CVE-2014-4344
• CVE-2013-6800
• CVE-2014-4345
• CVE-2014-4343
• CVE-2014-4342

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/6.6_Technical_Notes/krb5.html#RHSA-2014-1389