Final answer:
The type of UD described in the question is a security breach or information leak, which involves the transfer of classified information or CUI onto an unauthorized information system.
Step-by-step explanation:
The type of unauthorized disclosure (UD) described in the question is known as a security breach or information leak. This occurs when classified information or Controlled Unclassified Information (CUI) is transferred onto an information system that is not authorized at the appropriate security level or lacks the required CUI protection.
In the context of information security, organizations implement various measures to prevent security breaches and protect sensitive information. These measures may include strict access controls, encryption, regular security audits, and security awareness training for employees.
For example, imagine an employee of a government agency mistakenly saves classified documents onto a personal USB drive. If that USB drive is then plugged into an unauthorized computer, it would constitute a security breach and a violation of information security protocols.