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.
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.
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.
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.
Restricting access to the Squid proxy via access control lists or firewall rules may prevent this vulnerability from being exploited by remote attackers..
Vendor| Status| Date Notified| Date Updated
IPCop| | 10 Dec 2007| 11 Dec 2007
Red Hat, Inc.| | 10 Dec 2007| 11 Dec 2007
Squid| | -| 10 Dec 2007
SUSE Linux| | 10 Dec 2007| 18 Jan 2008
Apple Computer, Inc.| | 10 Dec 2007| 11 Dec 2007
Microsoft Corporation| | 10 Dec 2007| 11 Dec 2007
NetBSD| | 10 Dec 2007| 11 Dec 2007
Openwall GNU/*/Linux| | 10 Dec 2007| 11 Dec 2007
Slackware Linux Inc.| | 10 Dec 2007| 10 Dec 2007
Conectiva Inc.| | 10 Dec 2007| 10 Dec 2007
Cray Inc.| | 10 Dec 2007| 10 Dec 2007
Debian GNU/Linux| | 10 Dec 2007| 10 Dec 2007
EMC Corporation| | 10 Dec 2007| 10 Dec 2007
Engarde Secure Linux| | 10 Dec 2007| 10 Dec 2007
F5 Networks, Inc.| | 10 Dec 2007| 10 Dec 2007
If you are a vendor and your product is affected, let us know.
Group | Score | Vector
Base | N/A | N/A
Temporal | N/A | N/A
Environmental | N/A | N/A
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.