Lateral movement detection may be performed by employing different detection models to score logon sessions. The different detection models may be implemented by and/or utilize counts computed from historical security event data. The different detection models may include probabilistic intrusion detection models for detecting compromised behavior based on logon behavior, a sequence of security events observed during a logon session, inter-event time between security events observed during a logon session, and/or an attempt to logon using explicit credentials. Scores for each logon session that are output by the different detection models may be combined to generate a ranking score for each logon session. A list of ranked alerts may be generated based on the ranking score for each logon session to identify compromised authorized accounts and/or compromised machines. An attack graph may be automatically generated based on compromised account-machine pairs to visually display probable paths of an attacker.