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by John W. Simek, Vice President of Sensei Enterprises, Inc.

BEC Attacks Bypassing Microsoft 365 MFA

June 17, 2021

We’ve said it many times…enable multi-factor authentication (MFA) for ANY account. According to Microsoft’s own analysis, MFA will stop 99.9% of credential-based account attacks. However, don’t walk away with the false impression that MFA is 100% secure. Be wary of MFA codes that are sent via SMS text messages. There is a possibility that the code can be intercepted using SIM swapping or tricking you to enter the code into a false logon screen. Using an authentication app is a more secure alternative and push notifications are better yet.

As if the cyber world isn’t scary enough, cybercriminals have found a way to bypass MFA for Microsoft 365 accounts. Microsoft has a post describing the technical details of how a major BEC campaign is successfully getting around accounts with MFA. The post gets a little into the weeds, but the essential problem is connections being allowed via legacy methods such as IMAP/POP3. To protect you from this new breed of attack, make sure that your Microsoft 365 account has IMAP/POP3 disabled. You may have to get assistance from your IT support folks, but make it happen today.

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Digital Forensics/Cybersecurity/Information Technology