RHSA-2012:0683

Problem Description:

An updated bind-dyndb-ldap package that fixes one security issue is now
available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having
important security impact. A Common Vulnerability Scoring System (CVSS)
base score, which gives a detailed severity rating, is available from the
CVE link in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Server (v. 6) - i386, ppc64, s390x, x86_64
Red Hat Enterprise Linux Workstation (v. 6) - i386, x86_64

3. Description:

The dynamic LDAP back end is a plug-in for BIND that provides back-end
capabilities to LDAP databases. It features support for dynamic updates
and internal caching that help to reduce the load on LDAP servers.

A flaw was found in the way bind-dyndb-ldap handled LDAP query errors. If a
remote attacker were able to send DNS queries to a named server that is
configured to use bind-dyndb-ldap, they could trigger such an error with a
DNS query leveraging bind-dyndb-ldap's insufficient escaping of the LDAP
base DN (distinguished name). This would result in an invalid LDAP query
that named would retry in a loop, preventing it from responding to other
DNS queries. With this update, bind-dyndb-ldap only attempts to retry one
time when an LDAP search returns an unexpected error. (CVE-2012-2134)

Red Hat would like to thank Ronald van Zantvoort for reporting this issue.

All bind-dyndb-ldap users should upgrade to this updated package, which
contains a backported patch to correct this issue. For the update to take
effect, the named service must be restarted.

4. 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/knowledge/articles/11258

5. Bugs fixed (http://bugzilla.redhat.com/):

815846 - CVE-2012-2134 bind-dyndb-ldap: Bind DoS (named hang) by processing DNS query for zone served by bind-dyndb-ldap