CAN-SPAM Act - Section 5(a)(1) & 15 U.S.C. § 7704(a)(1)
Prohibits the transmission of electronic messages with materially false or misleading header information, aiming to prevent deceptive practices in commercial email communications.
Excerpt from regulation
(a) REQUIREMENTS FOR TRANSMISSION OF MESSAGES.--
(1) PROHIBITION OF FALSE OR MISLEADING TRANSMISSION INFORMATION.--It is unlawfal for any person to initiate the transmission, to a protected computer, of a commercial electronic mail message, or a transactional or relationship message, that contains, or is accompanied by, header information that is materially false or materially misleading. For purposes of this paragraph--
(A) header information that is technically accurate but includes an originating electronic mail address, domain name, or Internet Protocol address the access to which for purposes of initiating the message was obtained by means of false or fraudulent pretenses or representations shall be considered materially misleading;
(B) a "from" line (the line identifying or purporting to identify a person initiating the message) that accurately identifies any person who initiated the message shall not be considered materially false or materially misleading; and
(C) header information shall be considered materially misleading if it fails to identify accurately a protected computer used to initiate the message because the person initiating the message knowingly uses another protected computer to relay or retransmit the message for purposes of disguising its origin