The 'PUA - DefenderCheck Execution' detection rule is aimed at identifying the execution of the DefenderCheck tool on Windows systems. DefenderCheck is often utilized to analyze the signatures employed by Microsoft Defender, potentially aiding adversaries in evading antivirus detection by revealing how the antivirus identifies malicious elements. The detection rule monitors process creation events, particularly focusing on instances where the process image ends with 'DefenderCheck.exe' or where the process description explicitly mentions 'DefenderCheck'. Due to the tool's intended purpose of assessing AV signatures, it can be associated with defense evasion techniques classified under the ATT&CK framework, specifically T1027.005. The rule has a high confidence level in detecting this activity but maintains a low false positive rate, making it a reliable indicator for security analysts.