===================================================================== CERT-Renater Note d'Information No. 2021/VULN516 _____________________________________________________________________ DATE : 06/10/2021 HARDWARE PLATFORM(S): / OPERATING SYSTEM(S): Systems running Squid versions prior to 4.17, 5.2. ===================================================================== http://lists.squid-cache.org/pipermail/squid-announce/2021-October/000136.html http://lists.squid-cache.org/pipermail/squid-announce/2021-October/000139.html _____________________________________________________________________ __________________________________________________________________ Squid Proxy Cache Security Update Advisory SQUID-2020:12 __________________________________________________________________ Advisory ID: | SQUID-2020:12 Date: | Oct 03, 2021 Summary: | Out-Of-Bounds memory access in WCCPv2 Affected versions: | Squid 2.6 -> 2.7.STABLE9 | Squid 3.x -> 3.5.28 | Squid 4.x -> 4.16 | Squid 5.x -> 5.1 Fixed in version: | Squid 4.17 and 5.2 __________________________________________________________________ __________________________________________________________________ Problem Description: Due to an out of bounds memory access Squid is vulnerable to an information leak vulnerability when processing WCCPv2 messages. __________________________________________________________________ Severity: This problem allows a WCCPv2 sender to corrupt Squids list of known WCCP routers and divert client traffic to attacker controlled routers. This attack is limited to Squid proxy with WCCPv2 enabled and IP spoofing of a router IP address configured as trusted in squid.conf. CVSS Score of 7.7 __________________________________________________________________ Updated Packages: This bug is fixed by Squid versions 4.17 and 5.2. In addition, patches addressing this problem for the stable releases can be found in our patch archives: Squid 4: Squid 5: 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 built with --disable-wccpv2 are not vulnerable. All Squid-3.x up to and including 3.5.28 built with --enable-wccpv2 and configured with wccp2_router in squid.conf are vulnerable. All Squid-3.x up to and including 3.5.28 built without --disable-wccpv2 and configured with wccp2_router in squid.conf are vulnerable. All Squid-4.x up to and including 4.16 built with --enable-wccpv2 and configured with wccp2_router in squid.conf are vulnerable. All Squid-4.x up to and including 4.16 built without --disable-wccpv2 and configured with wccp2_router in squid.conf are vulnerable. All Squid-5.x up to and including 5.1 built with --enable-wccpv2 and configured with wccp2_router in squid.conf are vulnerable. All Squid-5.x up to and including 5.1 built without --disable-wccpv2 and configured with wccp2_router in squid.conf are vulnerable. __________________________________________________________________ Workaround: Either, The following network security Best Practices will greatly restrict the ability of any attacker utilizing this vulnerability. They can be considered workarounds for this issue: * Use Private IP address for control communications (eg WCCPv2) with routers. * Firewall restriction of UDP traffic on port 2048 and any other UDP ports used for WCCP(v2) control messages to only permit known devices to communicate with WCCP(v2). Note that ports used by clients and diverted by WCCP (eg 80 or 443) are not relevant. * Ensure the network implements BCP 38 spoofing protection. Include protection against LAN traffic spoofing as much as possible. See also and . Or, Build Squid with --disable-wccpv2 Or, Remove all lines for wccp2_* directives from squid.conf. The default configuration is not to enable WCCPv2. __________________________________________________________________ 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 you install and build Squid from the original Squid sources then the 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 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: This vulnerability was discovered by Lyu working with Trend Micro Zero Day Initiative. Fixed by Amos Jeffries of Treehouse Networks Ltd. __________________________________________________________________ Revision history: 2020-08-17 10:43:36 UTC Initial Report 2021-02-09 00:00:00 UTC Advisory Release by ZDI 2021-10-03 00:00:00 UTC Packages Released __________________________________________________________________ - -------------------------------------------------------------------------------- __________________________________________________________________ Squid Proxy Cache Security Update Advisory SQUID-2021:1 __________________________________________________________________ Advisory ID: | SQUID-2021:6 Date: | October 3, 2021 Summary: | Improper Certificate Validation in TLS Affected versions: | Squid 5.0.6 -> 5.1 Fixed in version: | Squid 5.2 __________________________________________________________________ __________________________________________________________________ Problem Description: When validating an origin server or peer certificate, Squid may incorrectly classify certain certificates as trusted. __________________________________________________________________ Severity: This problem allows a remote server to obtain security trust when the trust is not valid. This indication of trust may be passed along to clients allowing access to unsafe or hijacked services. This problem is guaranteed to occur when multiple CA have signed the TLS server certificate. It may also occur in cases of broken server certificate chains. CVSS Score of 8.4 __________________________________________________________________ Updated Packages: This bug is fixed by Squid version 5.2. In addition, patches addressing this problem for the stable releases can be found in our patch archives: Squid 5: 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-4 and older are not vulnerable. All Squid-5.0.1 up to and including 5.0.5 are not vulnerable. All Squid-5.0.6 up to and including 5.1 are vulnerable. __________________________________________________________________ Workaround: The only workaround is complete denial to TLS and HTTPS servers publishing affected certificate chains. The set of affected servers varies over time and is left out of this document. acl vulnerableDomains dstdomain .example.net http_access deny vulnerableDomains __________________________________________________________________ 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 you install and build Squid from the original Squid sources then the 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 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: This vulnerability was discovered by Jean-Paul Larocque of RodeoTV, LLC. Fixed by The Measurement Factory. __________________________________________________________________ Revision history: 2021-09-07 02:54:48 UTC Initial Report 2021-09-24 20:10:37 UTC Patches Released 2021-10-03 00:00:00 UTC Packages Released __________________________________________________________________ ========================================================= + CERT-RENATER | tel : 01-53-94-20-44 + + 23/25 Rue Daviel | fax : 01-53-94-20-41 + + 75013 Paris | email:cert@support.renater.fr + =========================================================