Suspicious Inbox Rule Hiding Mail to Deleted Items or RSS Feeds via AiTM BEC (via m365)

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1564.008Email Hiding Rules
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects creation or modification of a mailbox inbox rule that moves incoming messages to the Deleted Items, Archive, or RSS Feeds folders, the concealment behavior attackers apply after adversary-in-the-middle business email compromise to hide their activity from the legitimate user. Adversaries create these hide rules to suppress replies and security notices during fraud, making early detection critical for interrupting the compromise before financial loss.

Reporting behind it

Related detections9 linkedT1564.008 — drag to rearrange

Suspicious Inbox Rule Creation That Deletes Incoming Mail via Exchange (via m365)

Suspicious Exchange Inbox Forwarding Rule Creation via M365 (via m365)

Malicious Inbox Rule Hiding Security Mail to RSS Feeds via M365 (via m365)

Malicious Exchange Inbox Rule Hiding Direct Deposit and Bank Emails via Payroll Pirate Compromise (via m365)

Suspicious Inbox Rule Hiding Mail to Deleted Items via M365 Exchange

Suspicious SCATTERED SPIDER Exchange Transport Rule Creation to Suppress Alerts (via m365)

Suspicious Email-Hiding Inbox Rule Creation (via exchange)

Suspicious Inbox Rule Moving Mail to Junk for Concealment (via m365)

Detect Email Forwarding/Redirecting via Exchange PowerShell InboxRule Cmdlets on Windows

Suspicious Inbox Rule Hiding Mail to Deleted Items or RSS Feeds via AiTM BEC (via m365)

Pivot detection · T1564.008 · 9 related

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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