Cyber threats to contractor unclassified information systems represent an unacceptable risk of compromise of DoD information and pose an imminent threat to U.S. national security and economic security interests. This part requires all DoD contractors to rapidly report cyber incidents involving covered defense information on their covered contractor information systems or cyber incidents affecting the contractor's ability to provide operationally critical support. The part also permits eligible DoD contractors to participate in the voluntary DIB CS Program to share cyber threat information and cybersecurity best practices with DIB CS Program participants. The DIB CS Program enhances and supplements DIB CS Program participants' capabilities to safeguard DoD information that resides on, or transits, DIB unclassified information systems.