huntrule

PowerShell script alias obfuscation via -Value (-join(...))

Flags PowerShell script blocks that set aliases using -Value with a (-join(...)) character-joining obfuscation pattern.

FreeReviewedSigma · Low · v2
Product
windows
Category
ps_script
Author
Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2023-01-09
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Execution → Defense Evasion

  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 script content that includes both alias creation keywords (New-Alias/Set-Alias) and an obfuscated value built with the -Value (-join(...)) pattern. Attackers may use string joining to conceal alias targets within scripts and reduce straightforward inspection. It relies on Script Block Text containing the required substrings, such as "-Alias" and " -Value (-join(".

Reporting behind it

Related detections9 linkedT1027 — drag to rearrange
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Suspicious PS1Bot PowerShell Payload Written to ProgramData (via file_event)
Malicious Non-Interactive Encoded PowerShell Stager (via process_creation)
Suspicious Hidden PowerShell Executing Substring of Dropped File
PowerShell Encoded or Download-Cradle Command Line (via process_creation)
Obfuscated Encoded PowerShell Payload Deployed - PowerShell (via powershell)
Suspicious PowerShell AES Decryption and Reflective Method Invocation in SolarMarker
Suspicious PowerShell Invoking Remote HTA via Environment Variable Masquerading (via process_creation)
PowerShell script alias obfuscation via -Value (-join(...))
Pivot detection · T1027 · 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.