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Squid Proxy Cache Security Update Advisory SQUID-2023:10
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Advisory ID: | SQUID-2023:10
Date: | Dec 10, 2023
Summary: | Denial of Service in HTTP Request parsing
Affected versions: | Squid 2.6 -> 2.7.STABLE9
| Squid 3.1 -> 3.5.28
| Squid 4.x -> 4.17
| Squid 5.x -> 5.9
| Squid 6.x -> 6.5
Fixed in version: | Squid 6.6
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Problem Description:
Due to an Uncontrolled Recursion bug, Squid may be vulnerable to a
Denial of Service attack against HTTP Request parsing.
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Severity:
This problem allows a remote client to perform Denial of Service attack
by sending a large X-Forwarded-For header when the
follow_x_forwarded_for feature is configured.
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Updated Packages:
This bug is fixed by Squid version 6.6.
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_10.patch>
Squid 6:
<http://www.squid-cache.org/Versions/v6/SQUID-2023_10.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:
To check for follow_x_forwarded_for run the following command:
`squid -k parse 2>&1 |grep follow_x_forwarded_for`
All Squid configured without follow_x_forwarded_for are not
vulnerable.
All Squid older than 5.0.5 have not been tested and should be
assumed to be vulnerable when configured with
follow_x_forwarded_for.
All Squid-5.x up to and including 5.9 are vulnerable when
configured with follow_x_forwarded_for.
All Squid-6.x up to and including 6.5 are vulnerable when
configured with follow_x_forwarded_for.
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Workaround:
Remove all follow_x_forwarded_for lines from squid.conf
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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 Joshua Rogers of Opera
Software.
Fixed by Thomas Leroy of the SUSE security team.
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Revision history:
2023-10-12 11:53:02 UTC Initial Report
2023-11-28 07:35:46 UTC Patches Released
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END
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