Aspects of the disclosure relate to malware detection at endpoint devices. A computing platform may send rule information to a browser extension including a set of rules defining reportable behavior of network traffic associated with a website. Subsequently, the computing platform may receive report information including an identification of a loaded web page associated with the website that exhibits the reportable behavior defined by at least one rule of the set of rules and an indication of which rules of the set of rules have been met. Based on receiving the report information, the computing platform may assign a risk score for the identified loaded web page. Thereafter, the computing platform may determine that the risk score is above a predetermined threshold, and in response, the computing platform may send commands to the browser extension directing the browser extension to close the identified loaded web page.