Sigma rule: PowerShell Script Dropped Via PowerShell.EXE

Rule

Title

PowerShell Script Dropped Via PowerShell.EXE

Status

test

Level

low

Author

frack113

Date

2023-05-09

File

rules/windows/file/file_event/file_event_win_powershell_drop_powershell.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects PowerShell creating a PowerShell file (.ps1). While often times this behavior is benign, sometimes it can be a sign of a dropper script trying to achieve persistence.

Log source

product

windows

category

file_event

Detection

selection:
    Image|endswith:
        - '\powershell.exe'
        - '\pwsh.exe'
    TargetFilename|endswith: '.ps1'
filter_main_psscriptpolicytest:
    TargetFilename|contains: '__PSScriptPolicyTest_'
filter_main_appdata:
    TargetFilename|startswith: 'C:\Users\'
    TargetFilename|contains: '\AppData\Local\Temp\'
filter_main_windows_temp:
    TargetFilename|startswith: 'C:\Windows\Temp\'
condition: selection and not 1 of filter_main_*

False positives (as the rule lists them)

• False positives will differ depending on the environment and scripts used. Apply additional filters accordingly.

Tags

• attack.persistence

References

• https://www.zscaler.com/blogs/security-research/onenote-growing-threat-malware-distribution

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/file/file_event/file_event_win_powershell_drop_powershell.yml