Sigma rule: Suspicious PowerShell Download - Powershell Script

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-5c27f5b94a81, updated 2022-12-02T00:00:00.000Z.

Rule

Title
Suspicious PowerShell Download - Powershell Script
Status
test
Level
medium
Author
Florian Roth (Nextron Systems)
Date
2017-03-05
Modified
2022-12-02
File
rules/windows/powershell/powershell_script/posh_ps_susp_download.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects suspicious PowerShell download command

Log source

product
windows
category
ps_script
definition
Requirements: Script Block Logging must be enabled

Detection

webclient:
    ScriptBlockText|contains: 'System.Net.WebClient'
download:
    ScriptBlockText|contains:
        - '.DownloadFile('
        - '.DownloadFileAsync('
        - '.DownloadString('
        - '.DownloadStringAsync('
condition: webclient and download

False positives (as the rule lists them)

  • PowerShell scripts that download content from the Internet

Tags

  • attack.execution
  • attack.t1059.001

MITRE ATT&CK ids this rule names

Related rules

References

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/powershell/powershell_script/posh_ps_susp_download.yml

Sources and licences

  • SigmaHQ

    "Suspicious PowerShell Download - Powershell Script" by Florian Roth (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/powershell/powershell_script/posh_ps_susp_download.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Suspicious PowerShell Download - Powershell Script",
entity page, dataset version ref-5c27f5b94a81, updated 2022-12-02T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/403c2cc0-7f6b-4925-9423-bfa573bed7eb (accessed 2026-11-03).
Underlying source: SigmaHQ rule 403c2cc0-7f6b-4925-9423-bfa573bed7eb, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.