CVE-2023-6237

/// Technical description

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 applic

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References