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                                  CERT-Renater

                        Note d'Information No. 2023/VULN452

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DATE                : 06/11/2023

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running Squid versions prior to 6.4.

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https://github.com/squid-cache/squid/security/advisories/GHSA-73m6-jm96-c6r3
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SQUID-2023:4 Denial of Service in SSL Certificate validation
High
yadij published GHSA-73m6-jm96-c6r3

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 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 Andreas Weigel


Revision history:

2023-10-12 11:53:02 UTC Initial Report

END


Severity
High

8.6/ 10

CVSS base metrics

Attack vector
Network

Attack complexity
Low

Privileges required
None

User interaction
None

Scope
Changed

Confidentiality
None

Integrity
None

Availability
High

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
CWE-125 CWE-129 CWE-786 CWE-823 CWE-1285



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