CVE-2020-1464

CVE-2020-1464 is a spoofing vulnerability in Microsoft Windows caused by improper validation of file digital signatures (CWE-347). It is triggered when Windows accepts a file whose signature is malformed or improperly formed, treating it as validly signed. An attacker who can introduce such a file onto a system can bypass security features that depend on signature verification, allowing improperly signed files to load as if trusted — a common technique for malware delivery and defense evasion. Essentially all Microsoft Windows deployments on affected versions are exposed until patched. The flaw is listed in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03), confirming exploitation in the wild, though no public proof-of-concept is known and any ransomware linkage is unconfirmed.

What to do: Apply Microsoft's security updates for CVE-2020-1464 on all Windows systems per vendor instructions, prioritizing internet-facing and high-value endpoints, and verify patch coverage fleet-wide given the CISA KEV listing. Until patched, avoid relying solely on digital-signature-based trust decisions (e.g., application allowlisting or signature-gated file loading) for files of unknown origin.