Techniques for beacon and threat intelligence based Advanced Persistent Threat (APT) detection are disclosed. In some embodiments, a system/process/computer program product for beacon and threat intelligence based APT detection includes collecting firewall log data from monitored network traffic; analyzing the firewall log data at a cloud security service to identify beacon traffic based on a plurality of heuristics; performing a risk evaluation of the beacon traffic to detect malicious beacon traffic; and performing an action in response to detecting the malicious beacon traffic.