Due to chunked decoder lenience Squid is vulnerable to
Request/Response smuggling attacks when parsing HTTP/1.1
and ICAP messages.
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
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.
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.
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.
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@lists.squid-cache.org 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@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.
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.
Revision history:
2023-09-01 04:34:00 UTC Initial Report
2023-10-01 08:43:00 UTC Patch Available
END
Due to chunked decoder lenience Squid is vulnerable to
Request/Response smuggling attacks when parsing HTTP/1.1
and ICAP messages.
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
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.
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.
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.
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@lists.squid-cache.org 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@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.
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.
Revision history:
2023-09-01 04:34:00 UTC Initial Report
2023-10-01 08:43:00 UTC Patch Available
END