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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2011.0882.2 Squid Proxy Cache Security Update Advisory SQUID-2011:3 9 September 2011 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Squid 3.0 through 3.0.STABLE25 Squid 3.1 through 3.1.14 Squid 3.2 through 3.2.0.10 Publisher: Squid Operating System: Windows UNIX variants (UNIX, Linux, OSX) Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2011-3205 Original Bulletin: http://www.squid-cache.org/Advisories/SQUID-2011_3.txt Revision History: September 9 2011: Added CVE August 30 2011: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- __________________________________________________________________ Squid Proxy Cache Security Update Advisory SQUID-2011:3 __________________________________________________________________ Advisory ID: SQUID-2011:3 Date: August 28, 2011 Summary: Buffer overflow in Gopher reply parser Affected versions: Squid 3.0 -> 3.0.STABLE25 Squid 3.1 -> 3.1.14 Squid 3.2 -> 3.2.0.10 Fixed in Version: Squid 3.0.STABLE26, 3.1.15, 3.2.0.11 __________________________________________________________________ http://www.squid-cache.org/Advisories/SQUID-2005_1.txt http://www.squid-cache.org/Advisories/SQUID-2011_3.txt __________________________________________________________________ Problem Description: A bug exists in the code that parses responses from Gopher servers. The bug results in a buffer overflow if a Gopher server returns a line longer than 4096 bytes. The overflow results in memory corruption and usually crashes Squid. This is an extension of SQUID-2005:1 which has been opened in the Squid 3.x version code due to increased packet read sizes. __________________________________________________________________ Severity: A malicious user may set up a fake Gopher server and forward requests to it through Squid. Specially crafted responses from that server may cause Squid to restart. __________________________________________________________________ Updated Packages: This bug is fixed by Squid versions 3.2.0.11, 3.1.15, and 3.0.STABLE26. In addition, patches addressing this problem can be found in our patch archives. Squid-3.0: http://www.squid-cache.org/Versions/v3/3.0/changesets/squid-3.0-9193.patch Squid-3.1: http://www.squid-cache.org/Versions/v3/3.1/changesets/squid-3.1-10363.patch Squid-3.2: http://www.squid-cache.org/Versions/v3/3.2/changesets/squid-3.2-11294.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-2.x versions are not vulnerable. This problem is limited to Squid-3.x versions with large read buffer sizes. Unpatched Squid-3.0 releases up to and including 3.0.STABLE25 are vulnerable. Unpatched Squid-3.1 releases up to and including 3.1.14 are vulnerable. Unpatched Squid-3.2 releases up to and including 3.2.0.10 are vulnerable. __________________________________________________________________ Workarounds: Since real Gopher servers are extremely rare these days, there is almost no reason for Squid to contact a Gopher server. You can add a simple access control rule to deny all Gopher requests to Squid: acl Gopher proto Gopher http_access deny Gopher Restart or reconfigure Squid after editing squid.conf. Test your access controls with a simple request: % squidclient gopher://127.0.0.1/ You should see an "Access Denied" message. __________________________________________________________________ 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 found by Ben Hawkes, Google Security Team __________________________________________________________________ Revision history: 2011-08-28 12:29 GMT Initial release of this document __________________________________________________________________ - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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