Suspicious mailbox rule hides/forwards finance email threads

Ibrahim Saud@tektrix

•updated Sep 19, 2026•3•0•3

This rule monitors for the creation or modification of inbox rules in Microsoft 365 that contain financial-related keywords (e.g., 'payment', 'wire', 'invoice') and disruptive actions such as deleting, moving, forwarding, or redirecting messages. These patterns are characteristic of Business Email Compromise (BEC) attacks, where adversaries attempt to conceal financial correspondence from the victim to facilitate fraudulent transactions.