(RHSA-2014:1389) Moderate: krb5 security and bug fix update

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.