CVE-2023-5363 : Security Advisory and Response

This CVE record was published by OpenSSL on October 24, 2023, highlighting an issue related to the incorrect processing of cipher key and IV lengths in OpenSSL versions 3.0 and 3.1.

Understanding CVE-2023-5363

This vulnerability impacts the processing of key and initialization vector (IV) lengths in symmetric ciphers, leading to potential truncation or overruns during initialization, affecting specific ciphers and cipher modes.

What is CVE-2023-5363?

A bug in the key and IV lengths processing can cause truncation in the IV, potentially resulting in loss of confidentiality for certain cipher modes. The issue affects ciphers like RC2, RC4, RC5, CCM, GCM, and OCB within OpenSSL versions 3.0 and 3.1.

The Impact of CVE-2023-5363

Truncation of IVs can lead to non-uniqueness, impacting confidentiality in cipher modes like CCM, GCM, and OCB. The incorrect processing of key and IV lengths may result in memory exceptions, although not currently classified as security critical.

Technical Details of CVE-2023-5363

This vulnerability arises when calling specific EVP functions after establishing the key and IV. Alterations to key or IV lengths via OSSL_PARAM array parameters may not take effect as intended, potentially causing incorrect results and memory exceptions.

Vulnerability Description

The issue affects OpenSSL 3.0 and 3.1, where modifications to key and IV lengths may lead to incorrect cipher results and memory exceptions, impacting confidentiality in certain cipher modes.

Affected Systems and Versions

OpenSSL versions 3.0 and 3.1 are affected by this vulnerability, specifically impacting the processing of key and IV lengths in a manner that can compromise confidentiality in selected cipher modes.

Exploitation Mechanism

Exploitation of this vulnerability could result in non-uniqueness of IVs, potential loss of confidentiality in cipher modes, and incorrect cipher results due to key and IV length processing issues in specified OpenSSL versions.

Mitigation and Prevention

It is crucial to take immediate steps to address and mitigate the CVE-2023-5363 vulnerability in OpenSSL versions 3.0 and 3.1 to ensure the security of affected systems.

Immediate Steps to Take

Developers and system administrators should apply the necessary patches provided by OpenSSL to address the incorrect processing of cipher key and IV lengths, reducing the risk of potential confidentiality breaches and incorrect cipher results.

Long-Term Security Practices

Implementing robust security practices, including regular system updates, code reviews, and vulnerability assessments, can help prevent and mitigate similar vulnerabilities in the future.

Patching and Updates

Refer to the OpenSSL Advisory for CVE-2023-5363, which provides details on the vulnerability and necessary patch links for OpenSSL versions 3.0 and 3.1 to secure systems and prevent exploitation.