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Squid Proxy Cache Security Update Advisory SQUID-2016:5
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Advisory ID: SQUID-2016:5
Date: April 20, 2016
Summary: Buffer overflow in cachemgr.cgi
Affected versions: Squid 2.x all releases
Squid 3.x -> 3.5.16
Squid 4.x -> 4.0.8
Fixed in version: Squid 3.5.17, 4.0.9
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http://www.squid-cache.org/Advisories/SQUID-2016_5.txt
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-4051
CESG REF: 56397140 / VULNERABILITY ID: 394201
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Problem Description:
Due to incorrect buffer management Squid cachemgr.cgi tool is
vulnerable to a buffer overflow when processing remotely supplied
inputs relayed to it from Squid.
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Severity:
This problem allows any client to seed the Squid manager reports
with data that will cause a buffer overflow when processed by
the cachemgr.cgi tool.
However, this does require manual administrator actions to take
place. Which greatly reduces the impact and possible uses.
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Updated Packages:
This bug is fixed by Squid versions 3.5.17 and 4.0.9
In addition, patches addressing this problem for stable releases
can be found in our patch archives:
Squid 3.2:
<http://www.squid-cache.org/Versions/v3/3.2/changesets/SQUID-2016_5.patch>
Squid 3.3:
<http://www.squid-cache.org/Versions/v3/3.3/changesets/SQUID-2016_5.patch>
Squid 3.4:
<http://www.squid-cache.org/Versions/v3/3.4/changesets/SQUID-2016_5.patch>
Squid 3.5:
<http://www.squid-cache.org/Versions/v3/3.5/changesets/SQUID-2016_5.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:
Squid proxy is not vulnerable. The problem is isolated to the
manager CGI interface tool.
The vulnerability is also limited to reports displaying full URL
and/or similar unbounded values provided by the client. That
includes the reports:
filedescriptors, objects, vm_objects, active_requests,
client_list, and mem on certain systems.
cachemgr.cgi tool displays its version number in the HTML page
footer:
All 2.x versions up to and including 2.7.STABLE9 are vulnerable.
All 3.x versions up to and including 3.5.16 are vulnerable.
All 4.x versions up to and including 4.0.8 are vulnerable.
If your cachemgr.cgi does not display a version it is likely
to be one of the older vulnerable versions.
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Workaround:
Use tools other than cachemgr.cgi, such as squidclient to view
affected reports until the CGI tool can be patched or upgraded.
OR,
In recent Squid versions use the HTTP management interface
directly from the squid proxy to view affected reports.
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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 you install and build Squid from the original Squid sources
then the squid-users@xxxxxxxxxxxxxxx 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@xxxxxxxxxxxxxxx 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.
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Credits:
The vulnerability was discovered independently by CESG and
by Yuriy M. Kaminskiy.
Fixed by Amos Jeffries from Treehouse Networks Ltd.
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Revision history:
2016-04-15 10:54:39 GMT Initial Report
2016-04-20 03:54:54 GMT Patches Released
2016-04-20 13:42:00 GMT Packages Released
2016-04-20 15:47:01 GMT CVE Assigned
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END
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