Disclosed is a method of detecting whether a groupware user's behavior is an abnormal behavior. The method includes acquiring a uniform resource identifier (URI) from the user's behavior, generating a URI sequence from the URI on the basis of a predetermined time interval, preprocessing the URI sequence to generate a primitive URI sequence, calculating a log probability value from the primitive URI sequence, and detecting whether the user's behavior is an abnormal behavior on the basis of the log probability value and a predetermined threshold value.