CVE-2022-1343: 
Rust vulnerability analysis and mitigation

CVE-2022-1343 is a vulnerability discovered in OpenSSL's OCSP (Online Certificate Status Protocol) response verification functionality. The issue affects OpenSSL versions 3.0.0 through 3.0.2 and was fixed in version 3.0.3. The vulnerability relates to the OCSP_basic_verify function which verifies the signer certificate on an OCSP response. When using the non-default OCSP_NOCHECKS flag, the function incorrectly returns a positive verification result even when the response signing certificate fails to verify (OpenSSL Advisory).

The vulnerability exists in the OCSP_basic_verify function's certificate verification process. When the OCSPNOCHECKS flag is used, the function returns a successful verification even when the response signing certificate verification fails. In normal usage without the OCSPNOCHECKS flag, the function correctly returns a negative value for certificate verification failures. The issue also affects the OpenSSL command-line 'ocsp' application, where using the '-nocertchecks' option results in reporting successful verification despite actual failure, though error messages indicating the failure are still displayed (OpenSSL Advisory).

The vulnerability has been assessed with a CVSS v3.1 Base Score of 5.3 (MEDIUM) with the vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N. The primary impact is the potential for certificate verification bypass under specific conditions, which could lead to acceptance of invalid certificates when using the non-default OCSP_NOCHECKS flag (NVD).

The primary mitigation is to upgrade to OpenSSL version 3.0.3 or later, which contains the fix for this vulnerability. The fix was developed by Matt Caswell from OpenSSL. For systems that cannot be immediately upgraded, avoiding the use of the OCSP_NOCHECKS flag (which is non-default) will prevent exploitation of this vulnerability (OpenSSL Advisory).