huntrule

Suspicious Privilege Discovery Spawned by M365 Copilot Process

PremiumReviewedSigma · Medium · v1
Product
windows
Category
process_creation
Author
HuntRule
Published
2026-09-30
Updated
2026-09-30
AnalysisDetection

ATT&CK techniques

Discovery

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule detects whoami executed with the /priv argument as a child of M365Copilot.exe, an anomalous parentage observed in a Huntress-investigated Nightmare-Eclipse intrusion where the actor masqueraded execution under a trusted application. The Copilot binary has no legitimate reason to spawn privilege enumeration. This parent-child relationship indicates process masquerading paired with hands-on-keyboard discovery.

Reporting behind it

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Suspicious Security Software Discovery via tasklist and findstr (via process_creation)
Suspicious Security Process Enumeration via Tasklist And Findstr
Suspicious ESXi Virtual Machine Enumeration via esxcli Process List
Linux sysinfo Syscall for System Information Discovery
Windows: Recon command output piped to findstr.exe
Suspicious Privilege Discovery Spawned by M365 Copilot Process
Pivot detection · T1057 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.