Sigma Rule Library

Suspicious PowerShell Download - PoshModule

Detects suspicious PowerShell download command

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Detection logic

selection_webclient_

ContextInfo|contains: System.Net.WebClient

selection_function

ContextInfo|contains:
  - .DownloadFile(
  - .DownloadString(

Condition

all of selection_*

Raw YAML

title: Suspicious PowerShell Download - PoshModule
id: de41232e-12e8-49fa-86bc-c05c7e722df9
related:
    - id: 65531a81-a694-4e31-ae04-f8ba5bc33759
      type: derived
status: test
description: Detects suspicious PowerShell download command
references:
    - https://learn.microsoft.com/en-us/dotnet/api/system.net.webclient.downloadfile?view=net-8.0
    - https://learn.microsoft.com/en-us/dotnet/api/system.net.webclient.downloadstring?view=net-8.0
author: Florian Roth (Nextron Systems)
date: 2017-03-05
modified: 2023-01-20
tags:
    - attack.execution
    - attack.t1059.001
logsource:
    product: windows
    category: ps_module
    definition: 0ad03ef1-f21b-4a79-8ce8-e6900c54b65b
detection:
    selection_webclient_:
        ContextInfo|contains: 'System.Net.WebClient'
    selection_function:
        ContextInfo|contains:
            - '.DownloadFile('
            - '.DownloadString('
    condition: all of selection_*
falsepositives:
    - PowerShell scripts that download content from the Internet
level: medium

False positives

  • PowerShell scripts that download content from the Internet

References

  • derived65531a81-a694-4e31-ae04-f8ba5bc33759

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