An automatic data sanitizer module sanitizes formatted data from an external source system according to stored sanitization rules for release to an external destination system so that the destination system receives only that data for which it is authorized. The module generally includes an Input Comms module, a Message Processor, an Output Guard a Downgrader and an Output Comms module. The Input Comms module supports the communications protocol dictated by the external source system. The Processor sanitizes the message according to the rules written for the specific external system under consideration. The Guard verifies the modifications performed by the Processor. The Downgrader moves the resulting file to the Output Comms working directory and the Output Comms makes the resulting message available to the destination system. The system supports a variety of different formats and greatly facilitates the timely dissemination of information within a multi-level secure environment while protecting security interests.