Developing a high assurance multilevel mail server
Bradley R. Eads · Calhoun: The Naval Postgraduate School Institutional Archive (Naval Postgraduate School) · 1999
Electronic mail (email) often contains sensitive information, which requires special handling to prevent accidental disclosure to unauthorized personnel. Using multiple systems operating at different classifications has caused a number of inefficiencies in the way email is managed and distributed. Attachments in emails have increased the likelihood that a "Trojan Horse" could be inserted in the system to obtain unauthorized access to information. To address this problem Commercial Off-The-Shelf (COTS) software for Internet Message Access Protocol (IMAP), a mail server protocol, has been adapted to a high assurance multilevel base, the Wang Federal XTS-300. The XTS-300 constrains information flow permitting information at different sensitivity levels to be stored securely. Controlled access to mail is provided to client workstations. Enhanced with a trusted computing base extension, these COTS IBM PC compatibles run a standard office productivity suite. This architecture eliminates the risk that a "Trojan horse" will pass higher sensitivity information to a lower sensitivity level.