Activity specifications of a plurality of activities to be monitored are received. Each activity specification of the activity specifications identifies properties of a corresponding activity of the activities to be monitored. A fingerprint specification of a computer security risk fingerprint is received. The fingerprint specification identifies a combination of two or more of the activities to be detected. A log of activities to identify occurrences of the activities to be monitored is analyzed. Based on the analysis, the computer security risk fingerprint in the log of activities is detected, including by detecting an occurrence of at least a portion of the combination of the activities identified by the fingerprint specification. A computer security action based on the detection of the computer security risk fingerprint is performed.