huntrule

Suspicious PowerShell Module Usage with Hidden/Encoded Execution Parameters on Windows

Flags hidden or encoded PowerShell invocations that decode/execute code or download-and-execute patterns, while filtering a Chocolatey installer snippet.

FreeReviewedSigma · High · v2
Product
windows
Category
ps_module
Author
Florian Roth (Nextron Systems), Jonhnathan Ribeiro (SigmaHQ), DRL 1.1
Published
2017-03-05
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Execution

  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 flags PowerShell executions that include hidden or non-interactive invocation parameters combined with encoded or staged command execution patterns. It matters because attackers often use PowerShell to run payloads covertly via Base64 decoding, IEX-based execution, or encoded command options to reduce visibility. The detection relies on Windows telemetry containing PowerShell module ContextInfo strings with specific combinations of flags and command fragments (e.g., -nop, hidden windowing, -c with Convert.FromBase64String or iex/New-Object).

Reporting behind it

Related detections9 linkedT1059.001 — drag to rearrange
Suspicious Script Host Spawning Hidden PowerShell (via process_creation)
Suspicious PowerShell Reflective Assembly Load With GZip Decompression (via process_creation)
Suspicious PowerShell Invoke-Expression with Replace Obfuscation
Suspicious PowerShell Archive Extraction to AppData Roaming
Malicious PowerShell Spawned by Masqueraded NVIDIA GeForce Experience Binary
Suspicious PowerShell Hidden Unrestricted Execution via ClickFix
Suspicious PowerShell Spawned by cscript in Script Chain
Suspicious Script Interpreter Spawned by Explorer via ClickFix Run Dialog (via process_creation)
Suspicious PowerShell Download Cradle via ClickFix Fake CAPTCHA (via process_creation)
Suspicious PowerShell Module Usage with Hidden/Encoded Execution Parameters on Windows
Pivot detection · T1059.001 · 9 related

Changelog

v2
  1. v2
    Candidate ingested via manual entry.2026-07-31
  2. v1
    No changelog recorded for this version.2026-07-30

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