Cybersecurity researchers have called attention to an active "widespread email-driven phishing campaign" that employs adversary-in-the-middle (AitM) techniques to take control of Microsoft 365 accounts with an aim to identify key personnel involved in financial workflows and gather related email.
"The campaign uses residential proxies to disguise malicious sign-ins as ordinary consumer traffic," Arctic Wolf Labs said. "Automated activity maintains compromised sessions at approximately eight-hour intervals."
The activity is assessed to impact organizations across healthcare, education, manufacturing, government, and professional services sectors located in the U.S., Canada, and Europe. It shares tactical overlaps with Payroll Pirate attacks tracked by Microsoft under the moniker Storm-2755.
Payroll Pirates is the designation assigned to a broader financially motivated threat cluster that involves hijacking the accounts of employees to reroute salary payments to attacker-controlled accounts. Some aspects of these campaigns have been documented since early 2025, with Microsoft tracking a related threat as Storm-2657.
Arctic Wolf said it observed hundreds of organizations being targeted by email as part of the latest phishing campaign last month, resulting in successful intrusions spanning a broad range of victim environments.
