OpenSSL Security Advisory

Tue Mar 28 14:02:41 UTC 2023

Applications that use a non-default option when verifying certificates may be
vulnerable to an attack from a malicious CA to circumvent certain checks.

Invalid certificate policies in leaf certificates are silently ignored by
OpenSSL and other certificate policy checks are skipped for that certificate.
A malicious CA could use this to deliberately assert invalid certificate policies
in order to circumvent policy checking on the certificate altogether.

Policy processing is disabled by default but can be enabled by passing
the `-policy' argument to the command line utilities or by calling the
`X509_VERIFY_PARAM_set1_policies()' function.

Due to the low severity of this issue we are not issuing new releases of
OpenSSL at this time. The fix will be included in the next releases when they
become available. The fix is also available in commit facfb1ab (for 3.1),
commit 1dd43e07 (for 3.0), commit b013765a (for 1.1.1) in the OpenSSL
git repository, and commit 10325176 (for 1.0.2) in the OpenSSL git
repository for premium customers.

This issue was reported on 12th January 2023 by David Benjamin (Google).
The fix was developed by Matt Caswell.

Certificate policy check not enabled (CVE-2023-0466)
====================================================

Severity: Low

The function X509_VERIFY_PARAM_add0_policy() is documented to
implicitly enable the certificate policy check when doing certificate
verification. However the implementation of the function does not
enable the check which allows certificates with invalid or incorrect
policies to pass the certificate verification.

As suddenly enabling the policy check could break existing deployments it was
decided to keep the existing behavior of the X509_VERIFY_PARAM_add0_policy()
function.

Instead the applications that require OpenSSL to perform certificate
policy check need to use X509_VERIFY_PARAM_set1_policies() or explicitly
enable the policy check by calling X509_VERIFY_PARAM_set_flags() with
the X509_V_FLAG_POLICY_CHECK flag argument.

Certificate policy checks are disabled by default in OpenSSL and are not
commonly used by applications.

OpenSSL 3.1, 3.0, 1.1.1 and 1.0.2 are vulnerable to this issue.

Applications need to be updated if they are affected by the issue.

Due to the low severity of this issue we are not creating a new release at
this time. The documentation fix is also available in commit fc814a30
(for 3.1), commit 51e8a84c (for 3.0), commit 0d16b7e9 (for 1.1.1) in the
OpenSSL git repository, and commit 73398dea (for 1.0.2) in the OpenSSL git
repository for premium customers.

This issue was reported on 12th January 2023 by David Benjamin (Google).
The documentation fix was developed by Tomas Mraz.

General Advisory Notes
======================

URL for this Security Advisory:
https://www.openssl.org/news/secadv/20230328.txt

Note: the online version of the advisory may be updated with additional details
over time.

For details of OpenSSL severity classifications please see:
https://www.openssl.org/policies/secpolicy.html

OpenSSL 1.1.1 will reach end-of-life on 2023-09-11. After that date security
fixes for 1.1.1 will only be available to premium support customers.
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