The rule 'Startup Persistence by a Suspicious Process' identifies potentially malicious modifications made to the Windows Startup folder by processes typically associated with adversarial actions. Attackers often target the Startup folder to ensure their malicious programs execute upon user logon without direct interaction, thus maintaining persistence within the environment. This detection rule specifically monitors file write and modification events to the designated Startup folder paths, filtering out benign processes like system or service accounts. The rule leverages Elastic's EQL (Event Query Language) to inspect logs collected from various endpoints, ensuring comprehensive coverage across different Windows environments. Analysts can utilize the provided investigation guide during alerts to validate the legitimacy of the behaviors observed, perform potential remediation steps, and further enhance their incident response strategies. Overall, the rule assists in highlighting unauthorized persistence mechanisms employed by adversaries within a Windows infrastructure.