Sigma rule: Mail Forwarding/Redirecting Activity Via ExchangePowerShell Cmdlet

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-d94f3d3433ca, updated 2026-03-01T00:00:00.000Z.

Rule

Title
Mail Forwarding/Redirecting Activity Via ExchangePowerShell Cmdlet
Status
experimental
Level
medium
Author
Nasreddine Bencherchali (Nextron Systems), Marco Pedrinazzi (@pedrinazziM) (InTheCyber)
Date
2026-03-01
File
rules-threat-hunting/windows/powershell/powershell_script/posh_ps_email_forwarding_activity.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects email forwarding or redirecting activity via ExchangePowerShell Cmdlet

Log source

product
windows
category
ps_script
definition
Requirements: Script Block Logging must be enabled

Detection

selection_cmdlet:
    ScriptBlockText|contains:
        - 'New-InboxRule'
        - 'Set-InboxRule'
        - 'Set-Mailbox'
selection_params:
    ScriptBlockText|contains:
        - 'ForwardAsAttachmentTo'
        - 'ForwardingAddress'
        - 'ForwardingSmtpAddress'
        - 'ForwardTo'
        - 'RedirectTo' # Also covers "RedirectToRecipients"
condition: all of selection_*

False positives (as the rule lists them)

  • Legitimate mail forwarding rules created by users or administrators to forward email to designated internal or external recipients for business or operational purposes.

Tags

  • attack.collection
  • attack.stealth
  • attack.t1114.003
  • attack.t1564.008
  • attack.exfiltration
  • attack.t1020
  • detection.threat-hunting

MITRE ATT&CK ids this rule names

Related rules

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-threat-hunting/windows/powershell/powershell_script/posh_ps_email_forwarding_activity.yml

Sources and licences

  • SigmaHQ

    "Mail Forwarding/Redirecting Activity Via ExchangePowerShell Cmdlet" by Nasreddine Bencherchali (Nextron Systems), Marco Pedrinazzi (@pedrinazziM) (InTheCyber) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-threat-hunting/windows/powershell/powershell_script/posh_ps_email_forwarding_activity.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Mail Forwarding/Redirecting Activity Via ExchangePowerShell Cmdlet",
entity page, dataset version ref-d94f3d3433ca, updated 2026-03-01T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/0c7686d5-c74e-4292-b224-2a08e956ebc4 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 0c7686d5-c74e-4292-b224-2a08e956ebc4, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.