This detection rule analyzes failed trust validation attempts as recorded in Windows Event Logs, specifically targeting the CryptoAPI 2 (CAPI2) Operational logs for EventID 81. The rule triggers on messages indicating that the digital signature of an object could not be verified, which is a potential indicator of untrusted or malicious software execution attempts. Successful exploitation of this anomaly could allow an attacker to bypass security controls, leading to unauthorized code execution and possible system compromise. Given the criticality of secure software execution in Windows environments, monitoring for this event allows security teams to respond to and mitigate risks associated with potentially malicious binaries. Furthermore, care must be taken to minimize false positives that can arise from legitimate signatures failing validation due to user or system configuration changes.