Unholy trinity puts users in a BIND

DNS flaws threaten Net stability, again

Multiple vulnerabilities in older versions of BIND could lead to compromise and denial of service attacks against vulnerable Domain Name System servers, security tools vendor ISS warned last night.

The companies advises of three remotely exploitable flaws affecting BIND (Berkeley Internet Name Domain Server) 4 and BIND 8. The latest version of BIND, version 9, is immune to the problems. BIND 4 and 8 are still very widely deployed, however, making the flaws a real threat to overall Internet stability.

The vulnerabilities are: BIND SIG cached RR overflow flaw, which affects BIND 8, versions up to and including 8.3.3-REL and BIND 4, versions up to and including 4.9.10-REL; a BIND OPT DoS, affecting BIND 8, versions 8.3.0 up to and including 8.3.3-REL and a BIND SIG Expiry Time DoS, again hitting BIND 8, versions up to and including 8.3.3-REL. There's more detail of these flaws in ISS' advisory here.

Although there are no reports of active attacks using these particular bugs, ISS warns the flaws might lend themselves to automated attacks.

"Since the vulnerability is widespread, an Internet worm may be developed to propagate by exploiting
the flaws in BIND," it warns. "Widespread attacks against the DNS system may lead to general instability and inaccuracy of DNS data."

Users are advised to upgrade to BIND version 4.9.11, 8.2.7, 8.3.4 or to BIND version 9. These versions will be available soon here.

BIND is the most common implementation of the DNS protocol, is used on the vast majority of DNS servers on the Internet. DNS is an important Internet protocol that mediates links between a database of easy-to-remember domain names (host names) and their corresponding numerical IP addresses. ®

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