Invoke-Obfuscation STDIN+ Launcher

 1title: Invoke-Obfuscation STDIN+ Launcher
 2id: 6c96fc76-0eb1-11eb-adc1-0242ac120002
 3status: test
 4description: Detects Obfuscated use of stdin to execute PowerShell
 5references:
 6    - https://github.com/SigmaHQ/sigma/issues/1009  # (Task 25)
 7author: Jonathan Cheong, oscd.community
 8date: 2020-10-15
 9modified: 2024-04-15
10tags:
11    - attack.defense-evasion
12    - attack.t1027
13    - attack.execution
14    - attack.t1059.001
15logsource:
16    category: process_creation
17    product: windows
18detection:
19    selection:
20        # Example 1: c:\windows\sYstEm32\CmD.eXE /C"echO\Invoke-Expression (New-Object Net.WebClient).DownloadString | POwersHELl -NoEXiT -"
21        # Example 2: c:\WiNDOws\sysTEm32\cmd.EXe /C " ECHo Invoke-Expression (New-Object Net.WebClient).DownloadString | POwersHELl -nol ${EXEcUtIONCONTeXT}.INvOkEComMANd.InvOKEScRIPt( $InpUt )"
22        CommandLine|re: 'cmd.{0,5}(?:/c|/r).+powershell.+(?:\$\{?input\}?|noexit).+\"'
23    condition: selection
24falsepositives:
25    - Unknown
26level: high