CVE-2023-5363

OpenSSL Security Advisory [24th October 2023] ============================================= Incorrect cipher key & IV length processing (CVE-2023-5363) =========================================================== Severity: Moderate Issue summary: A bug has been identified in the processing of key and initialisation vector (IV) lengths. This can lead to potential truncation or overruns during the initialisation of some symmetric ciphers. Impact summary: A truncation in the IV can result in non-uniqueness, which could result in loss of confidentiality for some cipher modes. When calling EVP_EncryptInit_ex2(), EVP_DecryptInit_ex2() or EVP_CipherInit_ex2() the provided OSSL_PARAM array is processed after the key and IV have been established. Any alterations to the key length, via the “keylen” parameter or the IV length, via the “ivlen” parameter, within the OSSL_PARAM array will not take effect as intended, potentially causing truncation or overreading of these values. The following ciphers and cipher modes are impacted: RC2, RC4, RC5, CCM, GCM and OCB. For the CCM, GCM and OCB cipher modes, truncation of the IV can result in loss of confidentiality. For example, when following NIST’s SP 800-38D section 8.2.1 guidance for constructing a deterministic IV for AES in GCM mode, truncation of the counter portion could lead to IV reuse. Both truncations and overruns of the key and overruns of the IV will produce incorrect results and could, in some cases, trigger a memory exception. However, these issues are not currently assessed as security critical. Changing the key and/or IV lengths is not considered to be a common operation and the vulnerable API was recently introduced. Furthermore it is likely that application developers will have spotted this problem during testing since decryption would fail unless both peers in the communication were similarly vulnerable. For these reasons we expect the probability of an application being vulnerable to this to be quite low. However if an application is vulnerable then this issue is considered very serious. For these reasons we have assessed this issue as Moderate severity overall. The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this because the issue lies outside of the FIPS provider boundary. OpenSSL 3.1 and 3.0 are vulnerable to this issue. OpenSSL 3.0 users should upgrade to OpenSSL 3.0.12. OpenSSL 3.1 users should upgrade to OpenSSL 3.1.4. This issue was reported on 21st September 2023 by Tony Battersby of Cybernetics. The fix was developed by Dr Paul Dale. This problem was independently reported on the 3rd of December 2022 as part of issue #19822, but it was not recognised as a security vulnerability at that time. General Advisory Notes ====================== URL for this Security Advisory: https://www.openssl.org/news/secadv/20231024.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/general/security-policy.html OpenSSL 1.1.1 is out of support and no longer receiving public updates. Extended support is available for premium support customers: https://www.openssl.org/support/contracts.html