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Squid Proxy Cache Security Update Advisory SQUID-2019:1
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Advisory ID: SQUID-2019:1
Date: July 12, 2019
Summary: Denial of Service issue
in cachemgr.cgi
Affected versions: Squid 4.x -> 4.7
Fixed in version: Squid 4.8
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http://www.squid-cache.org/Advisories/SQUID-2019_1.txt
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-12854
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Problem Description:
Due to incorrect string termination the cachemgr.cgi may access
unallocated memory.
On systems with memory access protections this can result in
the CGI process terminating unexpectedly. Resulting in a
denial of service for all clients using it.
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Severity:
This problem allows a remote attacker with access to the Squid
manager API to perform a denial of service on other clients.
This problem is limited to the cachemgr CGI binary.
Web servers which run per-client instances of CGI tools are
affected by the issue, but the denial of service is not able to
affect other clients.
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Updated Packages:
This bug is fixed by Squid version 4.8.
In addition, patches addressing this problem for the stable
releases can be found in our patch archives:
Squid 4:
http://www.squid-cache.org/Versions/v4/changesets/squid-4-2981a957716c61ff7e21eee1d7d6eb5a237e466d.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 cachemgr.cgi 3.x and older versions are not vulnerable.
All cachemgr.cgi 4.x versions up to and including 4.7 are
vulnerable.
All Squid-4.7 and older versions accessed via the http:// URL
manager interface are not vulnerable.
To determine the version and interface, look at the footer of
manager reports for the "Generated by" string.
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Workarounds:
Either;
Convert to exclusively using the HTTP manager interface until
cachemgr.cgi can be upgraded to a fixed build.
Or;
Deny all access with 'manager' ACL in squid.conf.
This completely removes the vulnerability at cost of reduced
management and monitoring capabilities.
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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@xxxxxxxxxxxxxxxxxxxxx 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@xxxxxxxxxxxxxxxxxxxxx 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 Alex Rousskov of The
Measurement Factory.
Fixed by Amos Jeffries from Treehouse Networks Ltd.
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Revision history:
2019-04-10 21:13:50 UTC Initial Report
2019-05-18 09:43:41 UTC Patch Released
2019-06-16 10:52:51 UTC CVE Assignment
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END
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