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Squid Proxy Cache Security Update Advisory SQUID-2016:3
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Advisory ID: SQUID-2016:3
Date: April 02, 2016
Summary: Buffer overrun issue
in pinger ICMPv6 processing.
Affected versions: Squid 3.1.0 -> 3.5.15
Squid 4.0 -> 4.0.7
Fixed in version: Squid 4.0.8, 3.5.16
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http://www.squid-cache.org/Advisories/SQUID-2016_3.txt
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-3947
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Problem Description:
Due to a buffer overrun Squid pinger binary is vulnerable to
denial of service or information leak attack when processing
ICMPv6 packets.
This bug also permits the server response to manipulate other
ICMP and ICMPv6 queries processing to cause information leak.
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Severity:
This bug allows any remote server to perform a denial of service
attack on the Squid service by crashing the pinger. This may
affect Squid HTTP routing decisions. In some configurations,
sub-optimal routing decisions may result in serious service
degradation or even transaction failures.
If the system does not contain buffer-overrun protection leading
to that crash this bug will instead allow attackers to leak
arbitrary amounts of information from the heap into Squid log
files. This is of higher importance than usual because the pinger
process operates with root priviliges.
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Updated Packages:
This bug is fixed by Squid version 3.5.15 and 4.0.8.
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-3.1-10495.patch
Squid 3.2:
http://www.squid-cache.org/Versions/v3/3.2/changesets/squid-3.2-11839.patch
Squid 3.3:
http://www.squid-cache.org/Versions/v3/3.3/changesets/squid-3.3-12694.patch
Squid 3.4:
http://www.squid-cache.org/Versions/v3/3.4/changesets/squid-3.4-13232.patch
Squid 3.5:
http://www.squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-14015.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 versions are not vulnerable to this problem.
All Squid-3.0 versions are not vulnerable to this problem.
All Squid built with --disable-icmp are not vulnerable to this
problem.
All Squid built with --disable-ipv6 are not vulnerable to this
problem.
All Squid-3.x configured with "pinger_enable off" in squid.conf
are not vulnerable to this problem.
Check the server running processes list to determine if the Squid
service is running a "pinger" child process.
All unpatched Squid-3 versions up to and including 3.5.15
running the pinger process are vulnerable to this problem.
All unpatched Squid-4 versions up to and including 4.0.7
running the pinger process are vulnerable to this problem.
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Workaround:
Disable the pinger process in squid.conf:
pinger_enable off
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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:
The vulnerability was reported and fixed by Yuriy M. Kaminskiy.
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Revision history:
2016-02-21 23:42:28 GMT Initial Report
2016-03-28 22:52:58 GMT Patch Released
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END
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