Detectionhightest
PowerShell Execution With Potential Decryption Capabilities
Detects PowerShell commands that decrypt an ".LNK" "file to drop the next stage of the malware.
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X__Junior (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)Created Fri Jun 30Updated Tue Dec 05434c08ba-8406-4d15-8b24-782cb071a691windows
Log Source
WindowsProcess Creation
ProductWindows← raw: windows
CategoryProcess Creation← raw: process_creation
Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.
Detection Logic
Detection Logic4 selectors
detection:
selection_img:
Image|endswith:
- '\powershell.exe'
- '\pwsh.exe'
OriginalFileName:
- 'PowerShell.EXE'
- 'pwsh.dll'
selection_cli_dir:
CommandLine|contains:
- "Get-ChildItem "
- "dir "
- "gci "
- "ls "
selection_cli_gc:
CommandLine|contains:
- "Get-Content "
- "gc "
- 'cat '
- 'type '
- 'ReadAllBytes'
selection_cli_specific:
- CommandLine|contains|all:
- ' ^| '
- '\*.lnk'
- '-Recurse'
- '-Skip '
- CommandLine|contains|all:
- ' -ExpandProperty '
- '\*.lnk'
- 'WriteAllBytes'
- ' .length '
condition: all of selection_*False Positives
Unlikely
False positives are unlikely for most environments. High confidence detection.
References
MITRE ATT&CK
Tactics
Rule Metadata
Rule ID
434c08ba-8406-4d15-8b24-782cb071a691
Status
test
Level
high
Type
Detection
Created
Fri Jun 30
Modified
Tue Dec 05
Path
rules/windows/process_creation/proc_creation_win_powershell_decrypt_pattern.yml
Raw Tags
attack.execution