Query Details
References:https://www.microsoft.com/en-us/security/blog/2023/08/02/midnight-blizzard-conducts-targeted-social-engineering-over-microsoft-teams/
Use this Sentinel queries to hunt for apt29 teams phishing activity
OfficeActivity
| where UserId has_any ("msonlineservicesteam","mlcrosoftaccounts","msftonlineservices","msonlineteam","msftservice","noreplyteam","accounteam","teamsprotection","identityverification","msftprotection","accountsverification","azuresecuritycenter")
OfficeActivity
| where UserId endswith @"onmicrosoft.com" and UserId !endswith @"Yourdomain.onmicrosoft.com"
Filter for false positives
The query is looking for any suspicious activity related to phishing on Microsoft Teams by a group called Midnight Blizzard. It is filtering out false positives by excluding certain email domains.

Ali Hussein
Released: February 26, 2024
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