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SQUID-2023:3 Denial of Service in HTTP Digest Authentication

Critical
yadij published GHSA-phqj-m8gv-cq4g Oct 21, 2023

Package

squid

Affected versions

3.2.0.1-5.9, 6.0-6.3

Patched versions

6.4

Description

Due to a buffer overflow bug Squid is vulnerable to a Denial of
Service attack against HTTP Digest Authentication

Severity:

This problem allows a remote client to perform buffer overflow
attack writing up to 2 MB of arbitrary data to heap memory
when Squid is configured to accept HTTP Digest Authentication.

On machines with advanced memory protections this will result
in a Denial of Service against all users of the Squid proxy.

CVSS Score of 9.9
https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:H&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_3.patch

Squid 6:

http://www.squid-cache.org/Versions/v6/SQUID-2023_3.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 5.0.5 have not been tested and should be assumed
to be vulnerable.

All Squid-5.0.6 up to and including 5.9 are vulnerable.

All Squid-6.x up to and including 6.3 are vulnerable.

Workaround:

Disable HTTP Digest authentication until Squid can be
upgraded or patched.

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 Joshua Rogers of Opera
Software.

Fixed by Alex Bason.

Revision history:

2021-03-22 00:59:20 UTC Initial Report
2023-10-13 17:31:11 UTC Patch Published

END

Severity

Critical

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
Low
Integrity
Low
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:L/I:L/A:H

CVE ID

CVE-2023-46847

Weaknesses

Credits