__________________________________________________________________ Squid Proxy Cache Security Update Advisory SQUID-2020:1 __________________________________________________________________ Advisory ID: SQUID-2020:1 Date: February 03, 2020 Summary: Improper Input Validation issues in HTTP Request processing. Affected versions: Squid 2.x -> 2.7.STABLE9 Squid 3.x -> 3.5.28 Squid 4.x -> 4.9 Fixed in version: Squid 4.10 __________________________________________________________________ http://www.squid-cache.org/Advisories/SQUID-2020_1.txt http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8449 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8450 __________________________________________________________________ Problem Description: Due to incorrect input validation Squid can interpret crafted HTTP requests in unexpected ways to access server resources prohibited by earlier security filters. Due to incorrect buffer management a remote client can cause a buffer overflow in a Squid acting as reverse-proxy. __________________________________________________________________ Severity: This issue allows attackers to perform denial of service on the proxy and all clients using it. This issue potentially allows attackers to bypass security access controls in systems between client and proxy. This issue potentially allows remote code execution under the proxy low-privilege level. While restricted, it does have access to a wide range of information about the network structure and other clients using the proxy. This issue is limited to Squid acting as a reverse-proxy. Some effects also require allow_direct permissions. __________________________________________________________________ Updated Packages: This bug is fixed by Squid version 4.10. In addition, patches addressing this problem for the stable releases can be found in our patch archives: Squid 3.5: Squid 4.8 and older: Squid 4.9: 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 up to and including 2.7.STABLE9 with http_port 'accel' or 'vhost' options configured are vulnerable. All Squid-3.x up to and including 3.5.28 with http_port 'accel' or 'vhost' options configured are vulnerable. All Squid-4.x up to and including 4.9 with with http_port 'accel' option configured are vulnerable. To determine what port options are configured use the command: squid -k parse | grep -E _port __________________________________________________________________ Workarounds: There are no workarounds. __________________________________________________________________ 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@lists.squid-cache.org mailing list is your primary support point. For subscription details see . For reporting of non-security bugs in the latest STABLE release the squid bugzilla database should be used . For reporting of security sensitive bugs send an email to the squid-bugs@lists.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: Security Bypass and Server Side Request Forgery vulnerability was discovered by Regis Leroy (regilero from Makina Corpus). Denial of Service and Remote Code Execution vulnerability was discovered by Guido Vranken. Fixed by Amos Jeffries of Treehouse Networks Ltd. and Guido Vranken. __________________________________________________________________ Revision history: 2019-07-24 11:52:51 UTC Initial Report 2019-08-13 13:50:06 UTC Initial Patches Released 2019-10-05 02:05:23 UTC Additional Report 2019-12-12 03:27:40 UTC Additional Patches Released __________________________________________________________________ END