Several remote vulnerabilities have been discovered in BIND, an implementation of the DNS protocol suite. The Common Vulnerabilities and Exposures project identifies the following problems:
When DNSSEC validation is enabled, BIND does not properly handle certain bad signatures if multiple trust anchors exist for a single zone, which allows remote attackers to cause a denial of service (server crash) via a DNS query.
BIND does not properly determine the security status of an NS RRset during a DNSKEY algorithm rollover, which may lead to zone unavailability during rollovers.
BIND does not properly handle the combination of signed negative responses and corresponding RRSIG records in the cache, which allows remote attackers to cause a denial of service (server crash) via a query for cached data.
In addition, this security update improves compatibility with previously installed versions of the bind9 package. As a result, it is necessary to initiate the update with "apt-get dist-upgrade" instead of "apt-get update".
For the stable distribution (lenny), these problems have been fixed in version 1:9.6.ESV.R3+dfsg-0+lenny1.
For the upcoming stable distribution (squeeze) and the unstable distribution (sid), these problems have been fixed in version 1:9.7.2.dfsg.P3-1.
We recommend that you upgrade your bind9 packages.