@techreport{ietf-dkim-replay-problem-00, number = {draft-ietf-dkim-replay-problem-00}, type = {Internet-Draft}, institution = {Internet Engineering Task Force}, publisher = {Internet Engineering Task Force}, note = {Work in Progress}, url = {https://datatracker.ietf.org/doc/draft-ietf-dkim-replay-problem/00/}, author = {Wei Chuang and Dave Crocker and Allen Robin and Bron Gondwana}, title = {{DKIM Replay Problem Statement}}, pagetotal = 13, year = 2023, month = jul, day = 28, abstract = {DomainKeys Identified Mail (DKIM, RFC6376) permits claiming some responsibility for a message by cryptographically associating a domain name with the message. For data covered by the cryptographic signature, this also enables detecting changes made during transit. DKIM survives basic email relaying. In a Replay Attack, a recipient of a DKIM-signed message re-posts the message to other recipients,while retaining the original, validating signature, and thereby leveraging the reputation of the original signer. This document discusses the resulting damage to email delivery, interoperability, and associated mail flows. A significant challenge to mitigating this problem is that it is difficult for receivers to differentiate between legitimate forwarding flows and a DKIM Replay Attack.}, }