Question

A user forwards a suspicious email to the SOC. The message claims to be from the company's payroll provider and asks the recipient to log in via an included link. During analysis, the analyst reviews the raw email headers and notices the following: the 'From' header displays payroll@trustedvendor.com, but the SPF check result is 'softfail', the 'Return-Path' domain is mailer-3847.sendgrid-relay.ru, and DKIM shows 'none'. The Received chain originates from an IP not associated with the vendor's published mail infrastructure. Which conclusion is best supported by these indicators?

Accepted Answer

The sender domain is likely spoofed; the mismatched Return-Path, softfail SPF, and absent DKIM indicate the message did not originate from the authorized vendor infrastructure

Answer

The email is legitimate but was routed through a third-party marketing relay, so no action is needed

Answer

The DKIM 'none' result proves the message body was altered in transit and confirms a man-in-the-middle attack

Answer

Because the 'From' header matches the trusted vendor domain, the message passes authentication and can be released to the user