__________________________________________________________________ Squid Proxy Cache Security Update Advisory SQUID-2013:2 __________________________________________________________________ Advisory ID: SQUID-2013:2 Date: July 11, 2013 Summary: Buffer overflow in HTTP request handling Affected versions: Squid 3.2 -> 3.2.11, Squid 3.3 -> 3.3.6 Fixed in version: Squid 3.2.12, 3.3.7 __________________________________________________________________ http://www.squid-cache.org/Advisories/SQUID-2013_2.txt __________________________________________________________________ Problem Description: Due to incorrect data validation Squid is vulnerable to a buffer overflow attack when processing specially crafted HTTP requests. __________________________________________________________________ Severity: This problem allows any trusted client or client script who can generate HTTP requests to trigger a buffer overflow in Squid, resulting in a termination of the Squid service. __________________________________________________________________ Updated Packages: This bug is fixed by Squid versions 3.2.12 and 3.3.7. In addition, patches addressing the underlying problem for all Squid versions can be found in our patch archives. Squid 3.0: http://www.squid-cache.org/Versions/v3/3.0/changesets/squid-3.0-9200.patch Squid 3.1: http://www.squid-cache.org/Versions/v3/3.1/changesets/squid-3.1-10487.patch Squid 3.2: http://www.squid-cache.org/Versions/v3/3.2/changesets/squid-3.2-11823.patch Squid 3.3: http://www.squid-cache.org/Versions/v3/3.3/changesets/squid-3.3-12587.patch If you are using a prepackaged version of Squid then please refer to the package vendor for availability information on updated packages. __________________________________________________________________ Determining if your version is vulnerable: All Squid-3.1 and older versions, including Squid-2.x are not vulnerable. All unpatched Squid-3.2 versions up to and including 3.2.11 with 'intercept' or 'tproxy' option set on a http_port or https_port line in their squid.conf are vulnerable. All unpatched Squid-3.2 versions up to and including 3.2.11 with 'host_verify_strict' option set to ON in their squid.conf are vulnerable. All unpatched Squid-3.3 versions up to and including 3.3.6 with 'intercept' or 'tproxy' option set on a http_port or https_port line in their squid.conf are vulnerable. All unpatched Squid-3.3 versions up to and including 3.3.6 with 'host_verify_strict' option set to ON in their squid.conf are vulnerable. __________________________________________________________________ Workarounds: There are no workarounds for this issue when intercepting traffic with NAT or TPROXY. Use of transparent auto-configuration via WPAD and/or PAC is recommended practice instead of interception. If the vulnerability is due to use of the host_verify_strict directive in squid.conf. Removing it or setting it to OFF (the default) will remove the vulnerability for reverse-proxy and forward-proxy traffic. Any intercepted traffic will remain vulnerable. __________________________________________________________________ Contact details for the Squid project: For installation / upgrade support on binary packaged versions of Squid: Your first point of contact should be your binary package vendor. If your install and build Squid from the original Squid sources then the squid-users@squid-cache.org mailing list is your primary support point. For subscription details see <http://www.squid-cache.org/Support/mailing-lists.html>. For reporting of non-security bugs in the latest STABLE release the squid bugzilla database should be used <http://bugs.squid-cache.org/>. For reporting of security sensitive bugs send an email to the squid-bugs@squid-cache.org mailing list. It's a closed list (though anyone can post) and security related bug reports are treated in confidence until the impact has been established. __________________________________________________________________ Credits: The vulnerability was reported and fix provided by Nathan Hoad, Netbox Blue Pty Ltd __________________________________________________________________ Revision history: 2013-07-10 03:25 GMT Initial Report 2013-07-10 18:45 GMT Patches Released __________________________________________________________________ END