(LiveHacking.Com) – The Internet Systems Consortium (ISC) has released an update to BIND 9 to workaround a caching bug which is causing servers to crash all over the Internet. Reports from across the Internet show that BIND 9 based nameservers crash when performing recursive queries. There is a suggestion that this zero-day vulnerability is being used by hackers to launch a denial of service attack.
ISC have not yet identified how the crash is triggered (is it malformed packets, malformed requests etc) however it has discovered that once triggered the BIND 9 resolver caches an invalid record, then subsequent queries crash the server.
As a work around they have released patched versions of BIND 9.4-ESV, 9.6-ESV, 9.7 and 9.8, which makes the ‘named’ daemon recover gracefully from the inconsistency and so prevent the crash.
The release notes for the patched versions read:
BIND 9 nameservers performing recursive queries could cache an invalid record and subsequent queries for that record could crash the resolvers with an assertion failure.