__________________________________________________________________ Squid Proxy Cache Security Update Advisory SQUID-2018:2 __________________________________________________________________ Advisory ID: SQUID-2018:2 Date: Jan 19, 2018 Summary: Denial of Service issue in HTTP Message processing. Affected versions: Squid 3.x -> 3.5.27 Squid 4.x -> 4.0.22 Fixed in version: Squid 3.5.28, 4.0.23 __________________________________________________________________ http://www.squid-cache.org/Advisories/SQUID-2018_2.txt https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-1000027 __________________________________________________________________ Problem Description: Due to incorrect pointer handling Squid is vulnerable to denial of service attack when processing ESI responses or downloading intermediate CA certificates. __________________________________________________________________ Severity: This problem allows a remote client delivering certain HTTP requests in conjunction with certain trusted server responses to trigger a denial of service for all clients accessing the Squid service. __________________________________________________________________ Updated Packages: This bug is fixed by Squid version 4.0.23. In addition, patches addressing this problem for the stable releases can be found in our patch archives: Squid 3.5: Squid 4: 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 configured with "log_uses_indirect_client off" are not vulnerable. All Squid-3.0 versions built with --enable-esi and being used for reverse-proxy with squid.conf containing "log_uses_indirect_client on" are vulnerable. All Squid-3.1 and later versions up to and including Squid-3.5.27 being used for reverse-proxy with squid.conf containing "log_uses_indirect_client on" are vulnerable. All Squid-4 up to and including Squid-4.0.22 being used for reverse-proxy with squid.conf containing "log_uses_indirect_client on" are vulnerable. All unpatched Squid-4 up to and including Squid-4.0.22 being used for TLS/HTTPS intercept proxy with squid.conf containing "log_uses_indirect_client on" are vulnerable. __________________________________________________________________ Workarounds: Configure "log_uses_indirect_client off" in squid.conf __________________________________________________________________ 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: The initial issue was reported by Louis Dion-Marcil on behalf of GoSecure. Fixed by Amos Jeffries from Treehouse Networks Ltd. __________________________________________________________________ Revision history: 2017-12-13 20:09:30 UTC Initial Report 2018-01-18 23:10:00 UTC Patches Released 2018-01-21 07:45:00 UTC Advisory and fixed packages released 2018-07-28 04:24:00 UTC Update after 3.5.28 release __________________________________________________________________ END