The "Linux At Application Execution" detection rule is aimed at identifying potentially malicious use of the "at" and "atd" applications on Linux systems. These applications can be leveraged by attackers to establish persistence on compromised hosts by scheduling tasks that run at specified times. This rule utilizes data from Endpoint Detection and Response (EDR) systems, focusing on monitoring processes and their parent processes to catch any execution of the "at" or "atd" applications. Such activity can signal a threat, as it may indicate an attacker is attempting to maintain unauthorized access or deliver malicious payloads. The rule stresses the importance of immediate investigation upon triggering to assess the legitimacy of these actions, given their potential links to severe security incidents like data theft or ransomware attacks.