How should CUI be managed in email communications?

• A. Mark emails with the CUI designation, limit attachments, and use secure or encrypted channels for transmission.
• B. Do not mark emails and share freely.
• C. Attach all files regardless of size.
• D. Use non-secure channels for transmission.

Answer: (A)

Managing CUI in email centers on making sensitivity visible, limiting exposure, and protecting data in transit. Marking emails with the CUI designation ensures recipients understand they must handle the information under specific restrictions and apply the required controls. Limiting attachments reduces the opportunities for data leakage and keeps exposure to a minimum, focusing on what truly needs to be shared. Using secure or encrypted channels for transmission protects the content from interception or tampering as it travels between sender and recipient. Together, these practices create a safer, more controlled flow of information.

Not marking emails and sharing freely removes visibility and control; attaching all files regardless of necessity increases risk and burden; and using non-secure channels defeats encryption protections, making exposure more likely.