Potential PowerShell Execution Via DLL

 1title: Potential PowerShell Execution Via DLL
 2id: 6812a10b-60ea-420c-832f-dfcc33b646ba
 3status: test
 4description: |
 5    Detects potential PowerShell execution from a DLL instead of the usual PowerShell process as seen used in PowerShdll.
 6    This detection assumes that PowerShell commands are passed via the CommandLine.    
 7references:
 8    - https://github.com/p3nt4/PowerShdll/blob/62cfa172fb4e1f7f4ac00ca942685baeb88ff356/README.md
 9author: Markus Neis, Nasreddine Bencherchali (Nextron Systems)
10date: 2018/08/25
11modified: 2024/03/07
12tags:
13    - attack.defense_evasion
14    - attack.t1218.011
15logsource:
16    category: process_creation
17    product: windows
18detection:
19    selection_img:
20        - Image|endswith:
21              - '\InstallUtil.exe'
22              - '\RegAsm.exe'
23              - '\RegSvcs.exe'
24              - '\regsvr32.exe'
25              - '\rundll32.exe'
26        - OriginalFileName:
27              - 'InstallUtil.exe'
28              - 'RegAsm.exe'
29              - 'RegSvcs.exe'
30              - 'REGSVR32.EXE'
31              - 'RUNDLL32.EXE'
32    selection_cli:
33        CommandLine|contains:
34            - 'Default.GetString'
35            - 'DownloadString'
36            - 'FromBase64String'
37            - 'ICM '
38            - 'IEX '
39            - 'Invoke-Command'
40            - 'Invoke-Expression'
41    condition: all of selection_*
42falsepositives:
43    - Unknown
44level: high