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SQUID-2023:4 Denial of Service in SSL Certificate validation

High
yadij published GHSA-73m6-jm96-c6r3 Nov 1, 2023

Package

squid

Affected versions

3.3.0.1-5.9, 6.0-6.3

Patched versions

6.4

Description

Due to an Improper Validation of Specified Index
bug Squid is vulnerable to a Denial of Service
attack against SSL Certificate validation.

Severity:

This problem allows a remote server to perform Denial of
Service against Squid Proxy by initiating a TLS Handshake with
a specially crafted SSL Certificate in a server certificate
chain.

This attack is limited to HTTPS and SSL-Bump.

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 6.4.

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_4.patch

Squid 6:

http://www.squid-cache.org/Versions/v6/SQUID-2023_4.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:

All Squid older than 3.3.0.1 are not vulnerable.

All Squid-3.3 up to and including 3.4.14 compiled without
--enable-ssl are not vulnerable.

All Squid-3.3 up to and including 3.4.14 compiled using
--enable-ssl are vulnerable.

All Squid-3.5 up to and including 3.5.28 compiled without
--with-openssl are not vulnerable.

All Squid-3.5 up to and including 3.5.28 compiled using
--with-openssl are vulnerable.

All Squid-4.x up to and including 4.16 compiled without
--with-openssl are not vulnerable.

All Squid-4.x up to and including 4.16 compiled using
--with-openssl are vulnerable.

Squid-5.x up to and including 5.9 compiled without
--with-openssl are not vulnerable.

All Squid-5.x up to and including 5.9 compiled using
--with-openssl are vulnerable.

All Squid-6.x up to and including 6.3 compiled without
--with-openssl are not vulnerable.

All Squid-6.x up to and including 6.3 compiled using
--with-openssl are vulnerable.

Workaround:

Either,

Disable use of SSL-Bump features:

  • Remove all ssl-bump options from http_port and https_port
  • Remove all ssl_bump directives from squid.conf

Or,

Rebuild Squid using --without-openssl.

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 Andreas Weigel

Revision history:

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-2023-46724

Weaknesses

Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer. Learn more on MITRE.

Improper Validation of Array Index

The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array. Learn more on MITRE.

Access of Memory Location Before Start of Buffer

The product reads or writes to a buffer using an index or pointer that references a memory location prior to the beginning of the buffer. Learn more on MITRE.

Use of Out-of-range Pointer Offset

The product performs pointer arithmetic on a valid pointer, but it uses an offset that can point outside of the intended range of valid memory locations for the resulting pointer. Learn more on MITRE.

Improper Validation of Specified Index, Position, or Offset in Input

The product receives input that is expected to specify an index, position, or offset into an indexable resource such as a buffer or file, but it does not validate or incorrectly validates that the specified index/position/offset has the required properties. Learn more on MITRE.

Credits