[squid-users] [squid-announce] [ADVISORY] SQUID-2016:4 Denial of Service issue in HTTP Response processing.
squid3 at treenet.co.nz
Sat Apr 2 08:25:29 UTC 2016
Squid Proxy Cache Security Update Advisory SQUID-2016:4
Advisory ID: SQUID-2016:4
Date: April 02, 2016
Summary: Denial of Service issue
in HTTP Response processing.
Affected versions: Squid 3.x -> 3.5.15
Squid 4.x -> 4.0.7
Fixed in version: Squid 4.0.8, 3.5.16
Due to incorrect bounds checking Squid is vulnerable to a denial
of service attack when processing HTTP responses.
This problem allows a malicious client script and remote server
delivering certain unusual HTTP response syntax to trigger a
denial of service for all clients accessing the Squid service.
This bug is fixed by Squid version 3.5.16 and 4.0.8.
In addition, a patch addressing this problem for the stable
release can be found in our patch archives:
If you are using a prepackaged version of Squid then please refer
to the package vendor for availability information on updated
Determining if your version is vulnerable:
All unpatched Squid-3.0 versions are vulnerable.
All unpatched Squid-3.1 versions are vulnerable.
All unpatched Squid-3.2 versions are vulnerable.
All unpatched Squid-3.3 versions are vulnerable.
All unpatched Squid-3.4 versions are vulnerable.
All unpatched Squid-3.5 up to and including Squid-3.5.15 are
All unpatched Squid-4.0 up to and including 4.0.7 are vulnerable.
There are no good workarounds known for this vulnerability.
The following squid.conf settings can protect Squid-3.5 (only):
acl Vary rep_header Vary .
store_miss deny Vary
The following squid.conf setting can protect Squid-3.0 or later:
cache deny all
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
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
For reporting of non-security bugs in the latest STABLE release
the squid bugzilla database should be used
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.
This vulnerability was reported by Santiago R. Rincon of Debian.
Fixed by Amos Jeffries from Treehouse Networks Ltd.
2016-03-20 11:25:04 UTC Initial Report
2016-04-01 06:15:31 UTC Patch Released
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