Knowledge Base ISC Main Website Ask a Question/Contact ISC
CVE-2003-0914: BIND: Negative Cache DOS (negcache)
Author: Cathy Almond Reference Number: AA-00956 Views: 4533 Created: 2013-05-29 14:10 Last Updated: 2014-10-28 14:24 0 Rating/ Voters

A maliciously configured name server can trick a resolver into caching false no-such-name responses for long periods of time.

Posting date: 
04 Feb 2004
Program Impacted: 
Versions affected: 
All versions prior to 8.4.3 and 8.3.7, except some vendor-only releases

An attacker would configure a name server to return authoritative negative responses for a given target domain. Then, the attacker must convince a victim user to query the attacker's maliciously configured name server. When the attacker's name server receives the query, it will reply with an authoritative negative response containing a large TTL (time-to-live) value. If the victim's site runs a vulnerable version of BIND 8, it will cache the negative response and render the target domain unreachable until the TTL expires.


Disable recursion if possible, or limit recursion to specific clients.

Active exploits: 
None known at this time.

Upgrade to BIND 8.4.3 or later

© 2001-2018 Internet Systems Consortium

For assistance with problems and questions for which you have not been able to find an answer in our Knowledge Base, we recommend searching our community mailing list archives and/or posting your question there (you will need to register there first for your posts to be accepted). The bind-users and the dhcp-users lists particularly have a long-standing and active membership.

ISC relies on the financial support of the community to fund the development of its open source software products. If you would like to support future product evolution and maintenance as well having peace of mind knowing that our team of experts are poised to provide you with individual technical assistance whenever you call upon them, then please consider our Professional Subscription Support services - details can be found on our main website.

  • There is no feedback for this article
Quick Jump Menu