A security system and method for monitoring a security status of fixed and mobile assets. The security system comprises an agent connected with the asset. The agent includes a receiver for receiving; a sensing device for monitoring a security of the asset; a processor for compiling the a security data to generate a security status; and a wireless transceiver for transmitting data to a master control unit. The master control unit retransmits the security status to an global operations center for processing the security status to detect a security threat. In response to a security threat, the global operations center initiates and action or counter measure. For mobile assets the security system also tracks a location of the asset as the is transported between a shipper's loading dock and a designated distribution center, including an origination port and a destination port. For fixed agents, the security system includes an interface for interfacing an existing security device to the master control unit.