search menu icon-carat-right cmu-wordmark

CERT Coordination Center

BIND vulnerable to an assertion failure when querying for SIG records

Vulnerability Note VU#915404

Original Release Date: 2006-09-05 | Last Revised: 2006-10-02

Overview

A vulnerability in the BIND name server could allow a remote attacker to cause a denial of service against an affected system.

Description

The Berkeley Internet Name Domain (BIND) is a popular Domain Name System (DNS) implementation from Internet Systems Consortium (ISC). A flaw exists in the way that some versions of BIND handle DNS Security Extensions (DNSSEC) signed Resource Record Sets (RRsets).

The specific impact of this vulnerability is slightly different depending on the type of DNS server involved. For recursive servers, queries for SIG records will trigger an assertion failure if more than one SIG(covered) RRset is returned. For authoritative servers, if a name server is serving a RFC 2535 DNSSEC zone and is queried for the SIG records where there are multiple SIG(covered) RRsets (e.g., a zone apex) then the name server daemon will trigger an assertion failure when it tries to construct the response.

This vulnerability affects BIND 9.3.x versions 9.3.0, 9.3.1, 9.3.2, 9.3.3b, and 9.3.3rc1, and BIND 9.4.x versions 9.4.0a1, 9.4.0a2, 9.4.0a3, 9.4.0a4, 9.4.0a5, 9.4.0a6, and 9.4.0b1.

Impact

A remote attacker may be able to cause the name server daemon to crash, thereby causing a denial of service for DNS operations.

Solution

Apply a patch from the vendor

Patches have been released in response to this issue. Please see the Systems Affected section of this document.

Upgrade

Users who compile their own versions of BIND from the original ISC source code are encouraged to upgrade to BIND 9.3.2-P1. Patches for this issue are also included in BIND versions 9.3.3rc2 and 9.4.0b2. Patched versions of the software are available from the BIND download page.

Restrict Access

Administrators, particularly those who are unable to apply a patch, can limit exposure to this vulnerability by restricting sources that can ask for recursion.

Vendor Information

915404
 

View all 54 vendors View less vendors


CVSS Metrics

Group Score Vector
Base
Temporal
Environmental

References

Acknowledgements

Thanks to Joao Damas of the Internet Software Consortium for reporting this vulnerability.

This document was written by Chad R Dougherty.

Other Information

CVE IDs: CVE-2006-4095
Severity Metric: 7.83
Date Public: 2006-09-05
Date First Published: 2006-09-05
Date Last Updated: 2006-10-02 19:42 UTC
Document Revision: 15

Sponsored by CISA.