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Squid Proxy Cache Security Update Advisory SQUID-2023:1
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Advisory ID: | SQUID-2023:1
Date: | October 22, 2023
Summary: | Request/Response smuggling in HTTP(S) and ICAP
Affected versions: | Squid 2.6.STABLE10 -> 2.7.STABLE9
| Squid 3.x -> 3.5.28
| Squid 4.x -> 4.16
| Squid 5.x -> 5.9
| Squid 6.x -> 6.3
Fixed in version: | Squid 6.4
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Problem Description:
Due to chunked decoder lenience Squid is vulnerable to
Request/Response smuggling attacks when parsing HTTP/1.1
and ICAP messages.
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Severity:
This problem allows a remote attacker to perform
Request/Response smuggling past firewall and frontend security
systems when the upstream server interprets the chunked encoding
syntax differently from Squid.
This attack is limited to the HTTP/1.1 and ICAP protocols which
support receiving Transfer-Encoding:chunked.
CVSS Score of 9.3
<https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N&version=3.1>
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Updated Packages:
#This bug is fixed by Squid version 6.4.
In addition, patches addressing this problem for the stable
releases can be found in our patch archives:
Squid 5:
<http://www.squid-cache.org/Versions/v5/SQUID-2023_1.patch>
Squid 6:
<http://www.squid-cache.org/Versions/v6/SQUID-2023_1.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 older than 5.1 have not been tested and should be
assumed to be vulnerable.
All Squid-5.x up to and including 5.9 are vulnerable.
All Squid-6.x up to and including 6.3 are vulnerable.
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Workaround:
* ICAP issues can be reduced by ensuring only trusted ICAP
services are used, with TLS encrypted connections
(ICAPS extension).
* There is no workaround for the HTTP Request Smuggling issue.
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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@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
<https://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 Keran Mu and Jianjun Chen,
from Tsinghua University and Zhongguancun Laboratory.
Fixed by Amos Jeffries of Treehouse Networks Ltd.
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Revision history:
2023-09-01 04:34:00 UTC Initial Report
2023-10-01 08:43:00 UTC Patch Available
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END
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