Representatives of numerous organizations all over the Internet reported about crashes of BIND 9 DNS-servers performing recursive queries, which led to the denial of service. After the server crash there is an error logging in query.c saying: “INSIST(! dns_rdataset_isassociated(sigrdataset))».
All currently supported release versions of ISC BIND 9 are affected. The ISC development team is investigating the root of the problem and has already published patches, which help to prevent the server crash.
As far as it is known BIND 9 resolvers cached an invalid record, after what the resolvers could crash with an assertion failure, as a result of subsequent queries for this very record.
The released patch contains two components. The first one stops the cache from returning the inconsistent data, and the second – prevents DNS-server from crashing in case it receives an inconsistent answer of this nature.
