A method, system, and computer program product for identifying a malicious user obtain a plurality of service requests for a service provided by a processing system, each service request of the plurality of service requests being associated with a requesting user and a requesting system, and a plurality of service responses associated with the plurality of service requests, each service response of the plurality of service responses being associated with the processing system; and identify the requesting user as malicious based on the plurality of service requests and the plurality of service responses.