Source: Splunk Author: unknown URL: https://www.splunk.com/en_us/blog/security/hunting-m365-invaders-navigating-the-shadows-of-midnight-blizzard.html
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ONE SENTENCE SUMMARY: The blog discusses Microsoft’s cybersecurity incident involving Midnight Blizzard and develops detection strategies for similar attacks on M365 tenants.
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MAIN POINTS:
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Microsoft disclosed a cybersecurity incident attributed to the state-sponsored actor, Midnight Blizzard.
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The Splunk Threat Research Team analyzed the incident and shared detection strategies for defenders.
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Midnight Blizzard used password spray attacks on a non-MFA legacy tenant account.
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Detection engineers can identify traditional password spray attacks using specific error codes.
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The threat actor compromised an OAuth application with elevated access to corporate resources.
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Monitoring for application permission updates helps detect privilege escalation attacks in Entra ID.
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New OAuth applications can present monitoring challenges due to frequent legitimate triggers.
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Midnight Blizzard manipulated service principal privileges to bypass standard consent operations.
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Email details from compromised accounts can be tracked using the ‘Mailitemsaccessed’ event.
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Organizations must adapt detection strategies to address novel cloud attack vectors and misconfigurations.
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TAKEAWAYS:
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Be aware of potential threats from state-sponsored actors like Midnight Blizzard.
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Implement multifactor authentication (MFA) to secure tenant accounts against password spray attacks.
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Regularly monitor and audit OAuth applications and their associated permissions.
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Develop tailored detection analytics for unusual application activity in Entra ID.
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Strengthen understanding of cloud security threats and evolve detection strategies accordingly.