[squid-announce] [ADVISORY] SQUID-2016:8 Header smuggling issue in HTTP Request processing

[Amos Jeffries]

__________________________________________________________________

    Squid Proxy Cache Security Update Advisory SQUID-2016:8
__________________________________________________________________

Advisory ID:        SQUID-2016:8
Date:               May 06, 2016
Summary:            Header smuggling issue
                    in HTTP Request processing
Affected versions:  Squid 1.x -> 3.5.17
Fixed in version:   Squid 3.5.18
__________________________________________________________________

    http://www.squid-cache.org/Advisories/SQUID-2016_8.txt
    http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-4554
__________________________________________________________________

Problem Description:

 Due to incorrect input validation Squid is vulnerable to a header
 smuggling attack leading to cache poisoning and to bypass of
 same-origin security policy in Squid and some client browsers.

__________________________________________________________________

Severity:

 This problem allows a client to smuggle Host header value past
 same-origin security protections to cause Squid operating as
 interception or reverse-proxy to contact the wrong origin
 server. Also poisoning any downstream cache which stores the
 response.

 However, the cache poisoning is only possible if the caching
 agent (browser or explicit/forward proxy) is not following RFC
 7230 processing guidelines and lets the smuggled value through.

__________________________________________________________________

Updated Packages:

 This bug is fixed by Squid version 3.5.18

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

Squid 3.1:
 <http://www.squid-cache.org/Versions/v3/3.1/changesets/SQUID-2016_8.patch>

Squid 3.2:
 <http://www.squid-cache.org/Versions/v3/3.2/changesets/SQUID-2016_8.patch>

Squid 3.3:
 <http://www.squid-cache.org/Versions/v3/3.3/changesets/SQUID-2016_8.patch>

Squid 3.4:
 <http://www.squid-cache.org/Versions/v3/3.4/changesets/SQUID-2016_8.patch>

Squid 3.5:
 <http://www.squid-cache.org/Versions/v3/3.5/changesets/SQUID-2016_8.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 2.x versions up to and including 2.7.STABLE9 are vulnerable.

  All 3.x versions up to and including 3.5.17 are vulnerable.

  All 4.x versions are not vulnerable.

__________________________________________________________________

Workaround:

 There are no workarounds for this problem.

__________________________________________________________________

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 squid-users at 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 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 squid-cache.org mailing list. It is 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 reported by Jianjun Chen from Tsinghua
 University.

 Fixed by Amos Jeffries from Treehouse Networks Ltd.

__________________________________________________________________

Revision history:

 2016-04-26 09:29:13 UTC Initial Report
 2016-05-02 03:39:35 UTC Patches Released
 2016-05-06 13:12:00 UTC Packages Released
 2016-05-06 14:46:41 UTC CVE Assignment
 2016-05-08 12:45:58 UTC Patches Updated
__________________________________________________________________
END