Home Programs Emergency management Response CCIRC Analytical releases2 AV06-028: Multiple DoS vulnerabilities in the BIND 9 software

Multiple DoS vulnerabilities in the BIND 9 Software

Number: AV06-028
Date: 5 September 2006

Purpose

The purpose of this advisory is to bring attention to two vulnerabilities have been discovered that affect various versions of BIND 9. The first relates to SIG query processing and the second relates to a condition that can trigger an INSIST failure.

Assessment

172003/NISCC/BIND9/1: Assertion failure in ISC BIND SIG query processing CVE ID: CVE-2006-4095

• Recursive servers - Queries for SIG records will trigger an assertion failure if more than one RRset is returned. However exposure can be minimized by restricting which sources can ask for recursion.
• Authoritative servers - If a nameserver is serving a RFC 2535 DNSSEC zone and is queried for the SIG records where there are multiple RRsets, then the named program will trigger an assertion failure when it tries to construct the response.

172003/NISCC/BIND9/2: INSIST failure in ISC BIND recursive query handling code CVE ID: CVE-2006-4096

• It is possible to trigger an INSIST failure by sending enough recursive queries such that the response to the query arrives after all the clients waiting for the response have left the recursion queue. However exposure can be minimized by restricting which sources can ask for recursion.

If exploited, these vulnerabilities could potentially lead to a denial-of-service (DoS) condition.

Affected products

• BIND 9.3.0, BIND 9.3.1, BIND 9.3.2, BIND 9.3.3b1 and BIND 9.3.3rc1
• BIND 9.4.0a1, 9.4.0a2, 9.4.0a3, 9.4.0a4, 9.4.0a5, 9.4.0a6 and 9.4.0b1

Please note that although ISC has not been able to replicate these vulnerabilities in BIND 9.2.x, a patch is provided nonetheless.

Suggested action

PSEPC recommends that system administrators test and apply the latest security update as indicated for their supported product versions. BIND 9.3.2-P1 and BIND 9.2.6-P1 can be found via:

http://www.isc.org/sw/bind/

Note to readers

Canadian Cyber Incident Response Centre (CCIRC) collects information related to cyber threats to, and incidents involving, Canadian critical infrastructure. This allows us to monitor and analyze threats and to issue alerts, advisories and other information products. To report threats or incidents, please contact the Government Operations Centre (GOC) at 613-991-7000 or goc-cog@psepc-sppcc.gc.ca by e-mail.

Unauthorized use of computer systems and mischief in relation to data are serious Criminal Code offences in Canada. Any suspected criminal activity should be reported to local law enforcement organizations. The Royal Canadian Mounted Police (RCMP) National Operations Centre (N.O.C.) provides a 24/7 service to receive such reports or to redirect callers to local law enforcement organizations. The N.O.C. can be reached at 613-993-4460. National security concerns should be reported to the Canadian Security Intelligence Service (CSIS) at 613-993-9620.

For urgent matters or to report any incidents, please contact the Government Operations Centre at:

Phone: 613-991-7000
Fax: 613-996-0995
Secure Fax: 613-991-7094
Email: goc-cog@psepc-sppcc.gc.ca

For general information on critical infrastructure protection and emergency preparedness, please contact PSEPC's Public Affairs division at:

Telephone: 613-944-4875 or 1-800-830-3118
Fax: 613-998-9589
E-mail: communications@psepc-sppcc.gc.ca