RHSA-2012:0683 - Security Advisory

Topic

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.

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.

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

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.2 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.2 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.2 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.2 ppc64
• 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 Update Support from RHUI 6.2 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.2 i386
• Red Hat Storage 2.0 x86_64
• Red Hat Gluster Storage Server for On-premise 2.0 x86_64
• Red Hat Storage for Public Cloud (via RHUI) 2.0 x86_64
• Red Hat Enterprise Linux Server - AUS 6.2 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• 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 Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

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

CVEs

• CVE-2012-2134

References

• https://access.redhat.com/security/updates/classification/#important