"The handling of 'classified national security information' spillage is a Government-wide challenge. Current national policy does not provide guidance for handling such incidents. With the continued and ever increasing interconnection of information systems (ISs), the extent and risk of classified information spillage increase dramatically. This policy provides a framework for the consistent handling of spillage of classified information onto an unclassified IS, or higher-level classified information onto a lower level classified IS, to include non-government systems. Additional copies of this policy may be obtained from the Secretariat or the CNSS Website - www.cnss.gov."
CNSS Policy No. 18
Committee on National Security Systems: http://www.cnss.gov/