Abstract: Systems and methods are provided for monitoring and detecting intrusions and authenticating messages on a communication network of a vehicle. A plurality of signals transmitted over communications network between an electronic control module and a remote electronic module are monitored. Reflectometry feature sets are extracted from the plurality of signals and compared to a repository of predetermined communication network feature sets to generate a mismatch value. The mismatch value is compared to a predetermined threshold range and an authenticated event occurs when the mismatch value is within the predetermined threshold range. When the mismatch value is outside the predetermined threshold range, a flagged event occurs and is recorded.