CVE-2024-9355 identifies a vulnerability in the Golang FIPS OpenSSL cryptographic implementation where an uninitialized buffer length variable can be returned as zero in FIPS mode. This occurs due to improper initialization of a variable controlling buffer length, which can lead to a zeroed buffer being processed instead of the intended data. An attacker with the ability to supply input buffers can exploit this flaw to cause false positive matches between non-equal HMAC hashes by substituting a zeroed buffer for a pre-computed sum. Additionally, the vulnerability allows forcing a derived cryptographic key to be all zeros, compromising the unpredictability and security of key material. These issues can degrade the integrity and confidentiality of cryptographic operations, potentially impacting the Go TLS stack that relies on these primitives for secure communication. The vulnerability has a CVSS 3.1 score of 6.5, reflecting medium severity, with attack vector local, attack complexity high, privileges required low, no user interaction, and significant impact on confidentiality and integrity. No patches or exploits are currently reported, but the flaw poses a risk to systems relying on Golang FIPS OpenSSL for cryptographic assurances.

For European organizations, the impact of CVE-2024-9355 can be significant in environments where Golang FIPS OpenSSL is used for cryptographic operations, especially in sectors requiring FIPS compliance such as government, finance, and critical infrastructure. The vulnerability undermines the integrity of HMAC verification and key derivation processes, potentially allowing attackers to bypass authentication checks or decrypt sensitive communications if they can inject zeroed buffers. This could lead to unauthorized data access, data tampering, or man-in-the-middle attacks on TLS connections. The impact is heightened in systems that rely heavily on Go-based applications for secure communications or cryptographic functions. Although exploitation requires local access and has high complexity, insider threats or compromised internal systems could leverage this flaw. The absence of known exploits suggests limited immediate risk but does not preclude future attacks. Organizations may face compliance risks if cryptographic assurances are weakened, affecting trust and regulatory adherence.

Organizations should monitor for official patches or updates from Golang and OpenSSL maintainers and apply them promptly once available. Until patches are released, review and restrict local access to systems running Golang FIPS OpenSSL to trusted personnel only, minimizing the risk of local exploitation. Implement additional cryptographic validation layers where possible, such as verifying HMAC results through alternative methods or redundant checks to detect anomalies caused by zeroed buffers. Conduct thorough code audits of Go applications using FIPS OpenSSL to identify any reliance on vulnerable cryptographic functions and consider temporary workarounds like disabling FIPS mode if feasible and compliant. Enhance monitoring and logging around cryptographic operations to detect suspicious activity indicative of exploitation attempts. Educate developers and security teams about the vulnerability to ensure secure coding and operational practices. Finally, prepare incident response plans specific to cryptographic failures to quickly address potential breaches stemming from this vulnerability.