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SQUID-2023:9 Denial of Service in HTTP Collapsed Forwarding

High
yadij published GHSA-rj5h-46j6-q2g5 Dec 2, 2023

Package

squid

Affected versions

3.5-5.9

Patched versions

6.0.1

Description

Due to a Use-After-Free bug Squid is vulnerable to a Denial of
Service attack against collapsed forwarding


Severity:

This problem allows a remote client to perform Denial of
Service attack on demand when Squid is configured with collapsed
forwarding.

CVSS Score of 8.6
https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H&version=3.1


Updated Packages:

This bug is fixed by Squid version 6.0.1.

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:

Run the following command to identify how (and whether)
your Squid has been configured with collapsed forwarding:

`squid -k parse 2>&1 | grep collapsed_forwarding`

All Squid-3.5 up to and including 5.9 configured with
"collapsed_forwarding on" are vulnerable.

All Squid-3.5 up to and including 5.9 configured with
"collapsed_forwarding off" are not vulnerable.

All Squid-3.5 up to and including 5.9 configured without any
"collapsed_forwarding" directive are not vulnerable.


Workaround:

Remove all collapsed_forwarding lines from your squid.conf.


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 [email protected] 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
[email protected] 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 Joshua Rogers of Opera
Software.

Fixed by The Measurement Factory.


Revision history:

2022-09-03 18:41:32 UTC Patches Released
2023-10-12 11:53:02 UTC Initial Report


END

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

CVE ID

CVE-2023-49288

Weaknesses