CentOS 3 / 4 / 5 : bind / selinux-policy (CESA-2008:0533)
Medium Nessus Plugin ID 33448
SynopsisThe remote CentOS host is missing one or more security updates.
DescriptionUpdated bind packages that help mitigate DNS spoofing attacks are now available.
This update has been rated as having important security impact by the Red Hat Security Response Team.
[Updated 10th July 2008] We have updated the Enterprise Linux 5 packages in this advisory. The default and sample caching-nameserver configuration files have been updated so that they do not specify a fixed query-source port. Administrators wishing to take advantage of randomized UDP source ports should check their configuration file to ensure they have not specified fixed query-source ports.
ISC BIND (Berkeley Internet Name Domain) is an implementation of the DNS (Domain Name System) protocols.
The DNS protocol protects against spoofing attacks by requiring an attacker to predict both the DNS transaction ID and UDP source port of a request. In recent years, a number of papers have found problems with DNS implementations which make it easier for an attacker to perform DNS cache-poisoning attacks.
Previous versions of BIND did not use randomized UDP source ports. If an attacker was able to predict the random DNS transaction ID, this could make DNS cache-poisoning attacks easier. In order to provide more resilience, BIND has been updated to use a range of random UDP source ports. (CVE-2008-1447)
Note: This errata also updates SELinux policy on Red Hat Enterprise Linux 4 and 5 to allow BIND to use random UDP source ports.
Users of BIND are advised to upgrade to these updated packages, which contain a backported patch to add this functionality.
Red Hat would like to thank Dan Kaminsky for reporting this issue.
SolutionUpdate the affected bind and / or selinux-policy packages.