Vulnerability Note VU#198355

ISC BIND 8.2.2-P6 vulnerable to DoS when processing SRV records, aka the "srv bug"

Overview

There is a denial-of-service vulnerability in several versions of the Internet Software Consortium's (ISC) BIND software. This vulnerability is referred to by the ISC as the "srv bug" and affects ISC BIND versions 8.2 through 8.2.2-P6.

I. Description

This vulnerability can cause affected DNS servers running named to go into an infinite loop, thus preventing further name requests to be handled. This can happen if an SRV record (defined in RFC2782) is sent to the vulnerable server.

Microsoft's Windows 2000 Active Directory service makes extensive use of SRV records and is reportedly capable of triggering this bug in the course of normal operations. This is not, however, a vulnerability in Microsoft Active Directory. Any network client capable of sending SRV records to vulnerable name server systems can exercise this vulnerability.

II. Impact

A remote attacker can use malicious SRV records to crash vulnerable BIND servers, resulting in a denial-of-service condition that disables name resolution service.

III. Solution

Apply a patch from your vendor

To address this vulnerability, the CERT/CC recommends that all users of ISC BIND upgrade to version 8.2.2-P7, which patches both VU#198355 and VU#715973. For information regarding vendor-specific versions of DNS software, please consult the Systems Affected section of this document.

Systems Affected

Vendor	Status	Date Updated
Caldera	Unknown	16-May-2001
Compaq Computer Corporation	Vulnerable	16-May-2001
Conectiva	Unknown	11-May-2001
Debian	Vulnerable	16-May-2001
FreeBSD	Not Vulnerable	11-May-2001
Fujitsu	Not Vulnerable	11-May-2001
Hewlett Packard	Vulnerable	25-Jan-2002
IBM	Vulnerable	11-May-2001
Immunix	Unknown	11-May-2001
ISC	Vulnerable	11-May-2001
MandrakeSoft	Unknown	11-May-2001
Microsoft	Unknown	11-May-2001
NetBSD	Unknown	11-May-2001
RedHat	Unknown	11-May-2001
Slackware	Unknown	11-May-2001
SuSE	Vulnerable	11-May-2001
Trustix	Vulnerable	11-May-2001

References

http://www.isc.org/products/BIND/bind8.html
http://www.isc.org/products/BIND/bind-security.html

Credit

The CERT Coordination Center thanks Mark Andrews, David Conrad, and Paul Vixie of the ISC for developing a solution and assisting in the preparation of this document.

This document was written by Jeffrey S. Havrilla and Jeffrey P. Lanza.

Other Information

Date Public	11/07/2000
Date First Published	05/11/2001 09:44:25 AM
Date Last Updated	01/25/2002
CERT Advisory	CA-2000-20
CVE Name	CVE-2000-0888
US-CERT Technical Alerts
Metric	16.71
Document Revision	10

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