bind9 - cache poisoning

Michael Sinatra discovered that the DNS resolver component in BIND
does not properly check DNS records contained in additional sections
of DNS responses, leading to a cache poisoning vulnerability. This
vulnerability is only present in resolvers which have been configured
with DNSSEC trust anchors, which is still rare.

Note that this update contains an internal ABI change, which means
that all BIND-related packages (bind9, dnsutils and the library
packages) must be updated at the same time (preferably using “apt-get
update” and “apt-get upgrade”). In the unlikely event that you have
compiled your own software against libdns, you must recompile this
programs, too.

For the old stable distribution (etch), this problem has been fixed in
version 9.3.4-2etch6.

For the stable distribution (lenny), this problem has been fixed in
version 9.5.1.dfsg.P3-1+lenny1.

For the unstable distribution (sid) and the testing distribution
(squeeze), this problem has been fixed in version 9.6.1.dfsg.P2-1.

We recommend that you upgrade your bind9 packages.