BIND 9 DNS Dynamic Update Denial of Service Vulnerability

Receipt of a specially-crafted dynamic update message to a zone for which the server is the master may cause BIND 9 servers to exit. dns_db_findrdataset() fails when the prerequisite section of the dynamic update message contains a record of type "ANY" and where at least one RRset for this FQDN exists on the server.

Testing indicates that the attack packet has to be formulated against a zone for which that machine is a master. Launching the attack against slave zones does not trigger the assert.

This vulnerability affects all servers that are masters for one or more zones - it is not limited to those that are configured to allow dynamic updates. Access controls will not provide an effective workaround.

Note: The exploit code of this vulnerability is publicly available.