Microsoft sinks massive Office 365 email hacking campaign

Microsoft sinks massive Office 365 email hacking campaign
Microsoft 365 Defender researchers dismantled the cloud computing infrastructure that was used to orchestrate a large-scale business email compromise (BEC) campaign. In a joint blog post, Stefan Sellmer, Microsoft 365 Defender Research Team, and Nick Carr, Microsoft Threat Intelligence Center (MSTIC) share details about rogue cloud infrastructure that has spread across multiple web services. Cybersecurity researchers said the campaign compromised mailboxes using phishing and forwarding rules, in an attempt to obtain emails about financial transactions. “This survey also shows how cross-domain threat data, enriched with insights from expert analysts, provides protection against real-world threats, both in terms of attack detection through products like Microsoft Defender for Office 365, as well as in the removal of infrastructure. », Write the researchers. This campaign follows another equally comprehensive, but poorly executed BEC campaign, which used over a hundred farms occupied by typographical errors.

Stealth attacks

Microsoft's analysis revealed that attackers relied on a robust cloud infrastructure to automate their operations at scale. The attackers also found a way to bypass the use of multi-factor authentication (MFA) by exploiting legacy protocols like POP3/IMAP, which targets they forgot to turn off. By deciphering the attack vectors of this BEC attack, the researchers note that the campaign shows the stealthy nature of email campaigns that merge into legitimate traffic. The researchers also took the opportunity to showcase some of the mechanisms built into Office 365 that help it defend users against such BEC campaigns, including the use of artificial intelligence (AI) to detect abnormal behavior. They conclude by emphasizing the importance of developing a comprehensive defense strategy, including action steps before and after the breach. Via BleepingComputer