IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.

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PowerShell Script with Archive Compression Capabilities

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PowerShell Script with Archive Compression Capabilities

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Identifies the use of Cmdlets and methods related to archive compression activities. Adversaries will often compress and encrypt data in preparation for exfiltration.

Rule type: query

Rule indices:

winlogbeat-*
logs-windows.powershell*

Severity: low

Risk score: 21

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

Domain: Endpoint
OS: Windows
Use Case: Threat Detection
Tactic: Collection
Data Source: PowerShell Logs
Rule Type: BBR

Version: 208

Rule authors:

Elastic

Rule license: Elastic License v2

Setup

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Setup

The PowerShell Script Block Logging logging policy must be enabled. Steps to implement the logging policy with Advanced Audit Configuration:

Computer Configuration >
Administrative Templates >
Windows PowerShell >
Turn on PowerShell Script Block Logging (Enable)

Steps to implement the logging policy via registry:

reg add "hklm\SOFTWARE\Policies\Microsoft\Windows\PowerShell\ScriptBlockLogging" /v EnableScriptBlockLogging /t REG_DWORD /d 1

Rule query

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event.category:process and host.os.type:windows and
(
  powershell.file.script_block_text : (
    "IO.Compression.ZipFile" or
    "IO.Compression.ZipArchive" or
    "ZipFile.CreateFromDirectory" or
    "IO.Compression.BrotliStream" or
    "IO.Compression.DeflateStream" or
    "IO.Compression.GZipStream" or
    "IO.Compression.ZLibStream"
  ) and
  powershell.file.script_block_text : (
    "CompressionLevel" or
    "CompressionMode" or
    "ZipArchiveMode"
  ) or
  powershell.file.script_block_text : "Compress-Archive"
) and
not powershell.file.script_block_text : (
  "Compress-Archive -Path 'C:\ProgramData\Lenovo\Udc\diagnostics\latest" or
  ("Copyright: (c) 2017, Ansible Project" and "Ansible.ModuleUtils.Backup")
) and
not file.directory : "C:\Program Files\Microsoft Dependency Agent\plugins\lib"

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Collection
- ID: TA0009
- Reference URL: https://attack.mitre.org/tactics/TA0009/
Technique:
- Name: Archive Collected Data
- ID: T1560
- Reference URL: https://attack.mitre.org/techniques/T1560/
Tactic:
- Name: Execution
- ID: TA0002
- Reference URL: https://attack.mitre.org/tactics/TA0002/
Technique:
- Name: Command and Scripting Interpreter
- ID: T1059
- Reference URL: https://attack.mitre.org/techniques/T1059/
Sub-technique:
- Name: PowerShell
- ID: T1059.001
- Reference URL: https://attack.mitre.org/techniques/T1059/001/

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