Powershell Obfuscation and Escape Characters

 1title: Powershell Obfuscation and Escape Characters
 2id: bb1e6157-bc60-41fc-a395-513ed538fabe
 3status: experimental
 4description: Looks for the execution of PowerShell with unusually high counts of characters
 5    like ^, +, $, and %. Inspired by the 2022 Red Canary Threat Detection report.
 6references:
 7    - https://redcanary.com/threat-detection-report/techniques/powershell/
 8author: Micah Babinski
 9date: 2022/11/03
10tags:
11    - attack.execution
12    - attack.t1059.003
13    - attack.defense_evasion
14    - attack.t1027
15logsource:
16    category: process_creation
17    product: windows
18detection:
19    selection:
20        Image|endswith: '\powershell.exe'
21        # regex below detects five or more occurrences of the suspicious characters
22        CommandLine|re: '^([^^+$%]*[\^+$%]){5,}[^^+$%]*$'
23    condition: selection
24falsepositives:
25    - Unknown
26level: high```

References

• PowerShell - Red Canary Threat Detection Report

  

  PowerShell reclaimed its place as the most prevalent technique we detected in 2023, as adversaries continue to abuse the framework.

  
  Read More

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