Powershell Obfuscated Commands (RedCanary Threat Detection Report)

 1title: Powershell Obfuscated Commands (RedCanary Threat Detection Report)
 2id: df39fa21-d6b5-490e-85ef-d9b379707ac8
 3status: experimental
 4description: Detects powershell command line strings with high numbers of suspicious characters, potentially for obfuscation. Part of the RedCanary 2023 Threat Detection Report.
 5references:
 6    - https://redcanary.com/threat-detection-report/techniques/powershell/
 7author: RedCanary, Sigma formatting by Micah Babinski
 8date: 2023/05/10
 9tags:
10    - attack.execution
11    - attack.t1059.001
12logsource:
13    category: process_creation
14    product: windows
15detection:
16    selection:
17        Image|endswith: '\powershell.exe'
18        # regex below looks for eight or more total instances of the suspicious characters
19        CommandLine|re: '^([^^=%![(; ]*[\^=%![(; ]){8,}[^^=%![(; ]*$'
20    condition: selection
21falsepositives:
22    - Legitimate processes with long or convoluted command lines.
23level: low```