(1) Detecting proprietary data being transmitted from the computer. Extrusion detection provides alerts, whereas "extrusion prevention" attempts to stop sensitive data from being leaked out. See data extrusion.
(2) Detecting malware being transmitted from the computer. It is the opposite of an "intrusion detection system" (see IDS), which looks for incoming malware. Extrusion detection software determines if a computer is generating the attack.
