CVE-2023-0464 — Excessive Resource Usage Verifying X.509 Policy Constraints

Affected: OpenSSL

A security vulnerability has been identified in all supported versions

of OpenSSL related to the verification of X.509 certificate chains that include policy constraints. Attackers may be able to exploit this vulnerability by creating a malicious certificate chain that triggers exponential use of computational resources, leading to a denial-of-service (DoS) attack on affected systems.

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.

USN-6039-1 — openssl, openssl1.0 vulnerabilities

Affected: Ubuntu:Pro:14.04:LTS: openssl, Ubuntu:Pro:16.04:LTS: openssl, Ubuntu:18.04:LTS: openssl, Ubuntu:18.04:LTS: openssl1.0, Ubuntu:20.04:LTS: openssl, Ubuntu:22.04:LTS: openssl

It was discovered that OpenSSL was not properly managing file locks when processing policy constraints. If a user or automated system were tricked into processing a certificate chain with specially crafted policy constraints, a remote attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 22.04 LTS and Ubuntu 22.10. (CVE-2022-3996)

David Benjamin discovered that OpenSSL was not properly performing the verification of X.509 certificate chains that include policy constraints, which could lead to excessive resource consumption. If a user or automated system were tricked into processing a specially crafted X.509 certificate chain that includes policy constraints, a remote attacker could possibly use this issue to cause a denial of service. (CVE-2023-0464)

David Benjamin discovered that OpenSSL was not properly handling invalid certificate policies in leaf certificates, which would result in certain policy checks being skipped for the certificate. If a user or automated system were tricked into processing a specially crafted certificate, a remote attacker could possibly use this issue to assert invalid certificate policies and circumvent policy checking. (CVE-2023-0465)

David Benjamin discovered that OpenSSL incorrectly documented the functionalities of function X509_VERIFY_PARAM_add0_policy, stating that it would implicitly enable certificate policy checks when doing certificate verifications, contrary to its implementation. This…

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CVE-2023-0464 — Excessive Resource Usage Verifying X.509 Policy Constraints

USN-6039-1 — openssl, openssl1.0 vulnerabilities