Vulnerability Note VU#232881

Squid remote denial-of-service vulnerability

Overview

The Squid Proxy server contains a vulnerability that may allow an attacker to create a denial-of-service condition that affects the Squid server and systems that rely on it.

I. Description

Squid Proxy Cache is a caching proxy that supports the HTTP, HTTPS, and FTP protocols. Squid can also be deployed as a reverse proxy.

From Squid Proxy Cache Security Update Advisory SQUID-2007:2

Due to incorrect bounds checking Squid is vulnerable to a denial of service check during some cache update reply processing.

This incorrect bounds checking occurs within the httpHeaderUpdate() function when processing cache update replies.

II. Impact

An attacker who can access the Squid proxy may be able to cause the proxy server to crash. If the Squid proxy is deployed as a reverse proxy, the web servers relying on the proxy may also be affected.

III. Solution

Update

The Squid team has released patches 11780 and 11211 to address this issue. Administrators who obtain Squid from their operating system vendor should see the systems affected portion of this document for a partial list of affected vendors.

Restrict access

Restricting access to the Squid proxy via access control lists or firewall rules may prevent this vulnerability from being exploited by remote attackers..

Systems Affected

Vendor	Status	Date Notified
Apple Computer, Inc.	Not Vulnerable	11-Dec-2007
Conectiva Inc.	Unknown	10-Dec-2007
Cray Inc.	Unknown	10-Dec-2007
Debian GNU/Linux	Unknown	10-Dec-2007
EMC Corporation	Unknown	10-Dec-2007
Engarde Secure Linux	Unknown	10-Dec-2007
F5 Networks, Inc.	Unknown	10-Dec-2007
Fedora Project	Unknown	10-Dec-2007
FreeBSD, Inc.	Unknown	10-Dec-2007
Fujitsu	Unknown	10-Dec-2007
Gentoo Linux	Unknown	10-Dec-2007
Hewlett-Packard Company	Unknown	10-Dec-2007
Hitachi	Unknown	10-Dec-2007
IBM Corporation	Unknown	10-Dec-2007
IBM Corporation (zseries)	Unknown	10-Dec-2007
IBM eServer	Unknown	10-Dec-2007
Ingrian Networks, Inc.	Unknown	10-Dec-2007
IPCop	Vulnerable	11-Dec-2007
Juniper Networks, Inc.	Unknown	10-Dec-2007
Mandriva, Inc.	Unknown	10-Dec-2007
Microsoft Corporation	Not Vulnerable	11-Dec-2007
MontaVista Software, Inc.	Unknown	10-Dec-2007
NEC Corporation	Unknown	10-Dec-2007
NetBSD	Not Vulnerable	11-Dec-2007
Nokia	Unknown	10-Dec-2007
Novell, Inc.	Unknown	10-Dec-2007
OpenBSD	Unknown	10-Dec-2007
Openwall GNU/*/Linux	Not Vulnerable	11-Dec-2007
QNX, Software Systems, Inc.	Unknown	10-Dec-2007
Red Hat, Inc.	Vulnerable	11-Dec-2007
Silicon Graphics, Inc.	Unknown	10-Dec-2007
Slackware Linux Inc.	Not Vulnerable	10-Dec-2007
SmoothWall	Unknown	10-Dec-2007
Sony Corporation	Unknown	10-Dec-2007
Squid	Vulnerable	10-Dec-2007
Sun Microsystems, Inc.	Unknown	10-Dec-2007
SUSE Linux	Vulnerable	18-Jan-2008
The SCO Group	Unknown	10-Dec-2007
Trustix Secure Linux	Unknown	10-Dec-2007
Turbolinux	Unknown	10-Dec-2007
Ubuntu	Unknown	10-Dec-2007
Unisys	Unknown	10-Dec-2007
Wind River Systems, Inc.	Unknown	10-Dec-2007

References

http://www.squid-cache.org/Advisories/SQUID-2007_2.txt
http://wiki.squid-cache.org/SquidFaq/ReverseProxy
http://wiki.squid-cache.org/SquidFaq/SquidAcl#head-c87419712cac704d01cecc7da11cd02f489b6986
http://secunia.com/advisories/27910/

Credit

The Squid proxy team credits the Wikimedia Foundation for discovering this vulnerability. Adrian Chadd and Henrik Nordstrom are credited for authoring patches that address the issue.

This document was written by Ryan Giobbi.

Other Information

Date Public:	2007-11-27
Date First Published:	2007-12-10
Date Last Updated:	2008-01-18
CERT Advisory:
CVE-ID(s):	CVE-2007-6239
NVD-ID(s):	CVE-2007-6239
US-CERT Technical Alerts:
Metric:	7.51
Document Revision:	12

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Produced 2007 by US-CERT, a government organization
Disclaimers and copyright information

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