S 5.28 Acknowledging correct fax origin via telephone

Initiation responsibility: IT Security Management, Superiors

Implementation responsibility: Fax receiver

Consideration must be given as to whether the source of important or extraordinary fax messages should be confirmed by the sender to preclude forgeries by third parties. This acknowledgement can be provided easily via telephone. The relevant subscriber number should generally be documented on the fax cover sheet. It should, however, be verified as it could be forged.

Additional controls:

• Is the sender requested for confirmation via telephone in the case of important or unusual fax messages?