OpenSSL up to 3.0.12/3.1.4/3.2.0 RSA Public Key EVP_PKEY_public_check denial of service

Summaryinfo

A vulnerability was found in OpenSSL up to 3.0.12/3.1.4/3.2.0. It has been rated as problematic. Affected is the function EVP_PKEY_public_check of the component RSA Public Key Handler. The manipulation leads to denial of service. This vulnerability is listed as CVE-2023-6237. The attack may be initiated remotely. There is no available exploit. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in OpenSSL up to 3.0.12/3.1.4/3.2.0 (Network Encryption Software). This issue affects the function EVP_PKEY_public_check of the component RSA Public Key Handler. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. The summary by CVE is:

Issue summary: Checking excessively long invalid RSA public keys may take a long time. Impact summary: Applications that use the function EVP_PKEY_public_check() to check RSA public keys may experience long delays. Where the key that is being checked has been obtained from an untrusted source this may lead to a Denial of Service. When function EVP_PKEY_public_check() is called on RSA public keys, a computation is done to confirm that the RSA modulus, n, is composite. For valid RSA keys, n is a product of two or more large primes and this computation completes quickly. However, if n is an overly large prime, then this computation would take a long time. An application that calls EVP_PKEY_public_check() and supplies an RSA key obtained from an untrusted source could be vulnerable to a Denial of Service attack. The function EVP_PKEY_public_check() is not called from other OpenSSL functions however it is called from the OpenSSL pkey command line application. For that reason that application is also vulnerable if used with the '-pubin' and '-check' options on untrusted data. The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are affected by this issue.

The weakness was presented 01/15/2024 as 20240115.txt. The advisory is shared at openssl.org. The identification of this vulnerability is CVE-2023-6237 since 11/21/2023. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue. The advisory points out:

Applications that use the function EVP_PKEY_public_check() to check RSA public keys may experience long delays. Where the key that is being checked has been obtained from an untrusted source this may lead to a Denial of Service.

The vulnerability scanner Nessus provides a plugin with the ID 209841 (Fedora 40 : edk2 (2024-45df72afc6)), which helps to determine the existence of the flaw in a target environment.

Applying a patch is able to eliminate this problem. The advisory contains the following remark:

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 0b0f7abf (for 3.2), commit a830f551 (for 3.1) and commit 18c02492 (for 3.0) in the OpenSSL git repository.

The vulnerability is also documented in the vulnerability database at Tenable (209841). seclists.org is providing further details. If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Network Encryption Software

Name

• OpenSSL

Version

• 3.0
• 3.0.0
• 3.0.1
• 3.0.2
• 3.0.3
• 3.0.4
• 3.0.5
• 3.0.6
• 3.0.7
• 3.0.8
• 3.0.9
• 3.0.10
• 3.0.11
• 3.0.12
• 3.1
• 3.1.0
• 3.1.1
• 3.1.2
• 3.1.3
• 3.1.4
• 3.2.0

License

• open-source

Website

• Product: https://www.openssl.org/

CPE 2.3info

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CPE 2.2info

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