Sigma rule: Suspicious XOR Encoded PowerShell Command

Rule

Title

Suspicious XOR Encoded PowerShell Command

Status

test

Level

medium

Author

Sami Ruohonen, Harish Segar, Tim Shelton, Teymur Kheirkhabarov, Vasiliy Burov, oscd.community, Nasreddine Bencherchali

Date

2018-09-05

Modified

2023-01-30

File

rules/windows/process_creation/proc_creation_win_powershell_xor_commandline.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects presence of a potentially xor encoded powershell command

Log source

product

windows

category

process_creation

Detection

selection_img:
    - Image|endswith:
          - '\powershell.exe'
          - '\pwsh.exe'
    - OriginalFileName:
          - 'PowerShell.EXE'
          - 'pwsh.dll'
    - Description: 'Windows PowerShell'
    - Product: 'PowerShell Core 6'
selection_cli_xor:
    CommandLine|contains: 'bxor'
selection_cli_other:
    CommandLine|contains:
        - 'ForEach'
        - 'for('
        - 'for '
        - '-join '
        - "-join'"
        - '-join"'
        - '-join`'
        - '::Join'
        - '[char]'
condition: all of selection_*

False positives (as the rule lists them)

• Unknown

Tags

• attack.execution
• attack.stealth
• attack.t1059.001
• attack.t1140
• attack.t1027

MITRE ATT&CK ids this rule names

• T1027
• T1059.001
• T1140

Related rules

• 5b572dcf-254b-425c-a8c5-d9af6bea35a6 (obsolete)

References

• https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse?slide=65
• https://redcanary.com/blog/yellow-cockatoo/
• https://zero2auto.com/2020/05/19/netwalker-re/
• https://mez0.cc/posts/cobaltstrike-powershell-exec/

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