Knowledge Base ISC Main Website Ask a Question/Contact ISC
CVE-2000-0887: zxfr bug
Author: Cathy Almond Reference Number: AA-00945 Views: 4612 Created: 2013-05-29 13:55 Last Updated: 2014-10-28 13:53 100 Rating/ 1 Voters

A bug in code intended to provide support for the transfer of compressed zone files can result in the name server crashing.

Posting date: 
10 Nov 2000
Program Impacted: 
Versions affected: 
8.2.2 - 8.2.2-p6

named in BIND 8.2 through 8.2.2-P6 allows remote attackers to cause a denial of service by making a compressed zone transfer (ZXFR) request and performing a name service query on an authoritative record that is not cached, aka the "zxfr bug." This will disrupt name resolution service until the named daemon is restarted.


A partial workaround can be implemented by disallowing zone transfers except from trusted hosts. Note that if the trusted hosts are compromised, name servers with this bug will be vulnerable to denial of service attacks.

Active exploits: 
This attack can be implemented using utilities provided with the BIND package (named-xfer and dig).

Upgrade to 8.2.2-p7 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