Suspicious Exchange Online Mail Flow Rule or Connector Creation via Compromised Account
- Product
- m365
- Service
- exchange
- Author
- HuntRule
- Published
- 2026-05-27
- Updated
- 2026-08-28
ATT&CK techniques
Persistence → CollectionRecon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule detects creation or modification of Exchange Online transport rules, inbound connectors, or DKIM signing configuration, matching post-compromise mailbox tampering observed in the Kali365 device code phishing ecosystem. Adversaries add mail flow rules and connectors to reroute, hide, or spoof mail after taking over an account. These mailbox-infrastructure changes support business email compromise and mass phishing distribution.
Reporting behind it
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
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Also included
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