Debian Security Advisory

DSA-1604-1 bind -- DNS cache poisoning

Date Reported:
08 Jul 2008
Affected Packages:
Security database references:
In Mitre's CVE dictionary: CVE-2008-1447.
CERT's vulnerabilities, advisories and incident notes: VU#800113.
More information:

Dan Kaminsky discovered that properties inherent to the DNS protocol lead to practical DNS cache poisoning attacks. Among other things, successful attacks can lead to misdirected web traffic and email rerouting.

The BIND 8 legacy code base could not be updated to include the recommended countermeasure (source port randomization, see DSA-1603-1 for details). There are two ways to deal with this situation:

1. Upgrade to BIND 9 (or another implementation with source port randomization). The documentation included with BIND 9 contains a migration guide.

2. Configure the BIND 8 resolver to forward queries to a BIND 9 resolver. Provided that the network between both resolvers is trusted, this protects the BIND 8 resolver from cache poisoning attacks (to the same degree that the BIND 9 resolver is protected).

This problem does not apply to BIND 8 when used exclusively as an authoritative DNS server. It is theoretically possible to safely use BIND 8 in this way, but updating to BIND 9 is strongly recommended. BIND 8 (that is, the bind package) will be removed from the etch distribution in a future point release.