Vulnerability Note VU#817940

NetBSD malformed ICMPv6 MLD-QUERY denial of service

Overview

NetBSD fails to properly handle ICMPv6 MLD query packets, which can allow a remote, unauthenticated attacker to cause a denial of service.

I. Description

ICMPv6, which is defined in RFC 4443, is a version of the ICMP protocol for IPv6. Multicast Listener Discovery (MLD) for IPv6, which is defined in RFC 2710, uses ICMPv6 message types. MLD is used to discover the presence of multicast listeners on a router's directly attached links. MLD messages are sent with a link-local IPv6 source and a hop limit of one, which restricts the traffic to the local link. NetBSD fails to properly handle an ICMPv6 MLD-QUERY packet that has a Maximum-Response-Delay field set to the value of less than 0x0010. Upon receiving such a packet, code in the NetBSD kernel will attempt a division by zero and the system will stop.

II. Impact

An attacker on a local link can cause a NetBSD system to crash, resulting in a denial-of-service condition.

III. Solution

Apply an update

This issue is addressed in NetBSD Security Advisory 2008-011.

Systems Affected

Vendor	Status	Date Updated
NetBSD	Vulnerable	5-Sep-2008

References

http://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2008-011.txt.asc
http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/netinet6/mld6.c
http://cert.fi/haavoittuvuudet/2008/advisory-netbsd.html
http://tools.ietf.org/html/rfc4443
http://tools.ietf.org/html/rfc2710

Credit

Thanks to CERT-FI Vulnerability Coordination for reporting this vulnerability, who in turn credit Codenomicon.

This document was written by Will Dormann.

Other Information

Date Public	08/22/2008
Date First Published	09/05/2008 11:16:47 AM
Date Last Updated	09/05/2008
CERT Advisory
CVE Name	CVE-2008-2464
Metric	3.12
Document Revision	10

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