[squid-announce] [ADVISORY] SQUID-2018:3 Denial of Service issue in ESI Response processing.

[Amos Jeffries]

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    Squid Proxy Cache Security Update Advisory SQUID-2018:3
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Advisory ID:        SQUID-2018:3
Date:               April 18, 2018
Summary:            Denial of Service issue
                    in ESI Response processing.
Affected versions:  Squid 3.1.12.2 -> 3.1.23
                    Squid 3.2.0.8 -> 3.2.14
                    Squid 3.3 -> 4.0.12
Fixed in version:   Squid 4.0.13
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    http://www.squid-cache.org/Advisories/SQUID-2018_3.txt
    http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-1172
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Problem Description:

 Due to incorrect pointer handling Squid is vulnerable to denial
 of service attack when processing ESI responses.

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Severity:

 This problem allows a remote server delivering ESI responses
 to trigger a denial of service for all clients accessing the
 Squid service.

 This problem is limited to Squid operating as reverse proxy.

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Updated Packages:

 This bug is fixed by Squid version 4.0.13.

 In addition, patches addressing this problem for the stable
 releases can be found in our patch archives:

Squid 3.5:
 <http://www.squid-cache.org/Versions/v3/3.5/changesets/SQUID-2018_3.patch>

 If you are using a prepackaged version of Squid then please refer
 to the package vendor for availability information on updated
 packages.

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Determining if your version is vulnerable:

 All Squid-2.x and older are not vulnerable.

 All Squid-3.0 and older version are not vulnerable.

 All Squid built with --disable-esi are not vulnerable.

 All Squid-3.x versions up to and including 3.4.14 built with
 --disable-ssl are not vulnerable.

 All Squid-3.x versions up to and including 3.4.14 built without
 --enable-ssl are not vulnerable.

 All Squid-3.x versions up to and including 3.5.27 built without
 --enable-esi are not vulnerable.

 All Squid-3.1.12.2 and later versions up to and including
 Squid-3.1.23 built with --enable-esi and--enable-ssl, and being
 used for reverse-proxy are vulnerable.

 All Squid-3.2.0.8 and later versions up to and including
 Squid-3.2.14 built with --enable-esi and --enable-ssl, and being
 used for reverse-proxy are vulnerable.

 All Squid-3.3 and later versions up to and including
 Squid-3.3.14 built with --enable-esi and --enable-ssl, and being
 used for reverse-proxy are vulnerable.

 All Squid-3.4 and later versions up to and including
 Squid-3.4.14 built with --enable-esi and --enable-ssl, and being
 used for reverse-proxy are vulnerable.

 All Squid-3.5 versions up to and including 3.5.27 built without
 --with-openssl are not vulnerable.

 All Squid-3.5 and later versions up to and including 3.5.27 built
 with --enable-esi and --with-openssl, and being used for
 reverse-proxy are vulnerable.

 All Squid-4 versions up to and including 4.0.12 built without
 --with-openssl are not vulnerable.

 All Squid-4 versions up to and including 4.0.12 built with
 --with-openssl and being used for reverse-proxy are vulnerable.

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Workarounds:

Either;

 Build Squid with --disable-esi

Or,

 Build Squid-3.1 to 3.4.14 or later with "--disable-ssl"

Or,

 Build Squid-3.5 or later with "--without-openssl"

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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 at lists.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 at 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.

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Credits:

 This vulnerability was discovered by Michael Marshall of Trend
 Micro working with Trend Micro's Zero Day Initiative.

 Fixed by Christos Tsantilas on behalf of Measurement Factory.

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Revision history:

 2018-04-16 18:20:15 UTC Initial Report
 2018-04-16 22:02:25 UTC Patches Released
 2018-04-18 12:28:00 UTC Advisory Released
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