sigmamediumHunting

Suspicious Unblock-File

Remove the Zone.Identifier alternate data stream which identifies the file as downloaded from the internet.

MITRE ATT&CK

defense-evasion

Detection Query

selection:
  ScriptBlockText|contains|all:
    - "Unblock-File "
    - "-Path "
condition: selection

Author

frack113

Created

2022-02-01

Data Sources

windowsps_script

Platforms

windows

References

Tags

attack.defense-evasionattack.t1553.005

Raw Content

title: Suspicious Unblock-File
id: 5947497f-1aa4-41dd-9693-c9848d58727d
status: test
description: Remove the Zone.Identifier alternate data stream which identifies the file as downloaded from the internet.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1553.005/T1553.005.md#atomic-test-3---remove-the-zoneidentifier-alternate-data-stream
    - https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/unblock-file?view=powershell-7.2
author: frack113
date: 2022-02-01
tags:
    - attack.defense-evasion
    - attack.t1553.005
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains|all:
            - 'Unblock-File '
            - '-Path '
    condition: selection
falsepositives:
    - Legitimate PowerShell scripts
level: medium