Suspicious .NET Reflection via PowerShell

Detects the use of Reflection.Assembly to load PEs and DLLs in memory in PowerShell scripts. Attackers use this method to load executables and DLLs without writing to the disk, bypassing security solutions.

Rule type: query

Rule indices:

winlogbeat-*
logs-windows.*

Severity: high

Risk score: 73

Runs every: 5m

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

Maximum alerts per execution: 100

References:

https://docs.microsoft.com/en-us/dotnet/api/system.reflection.assembly.load

Tags:

Elastic
Host
Windows
Threat Detection
Defense Evasion

Version: 2

Rule authors:

Elastic

Rule license: Elastic License v2

Rule query

edit

event.category:process and
  powershell.file.script_block_text : (
    "[System.Reflection.Assembly]::Load" or
    "[Reflection.Assembly]::Load"
  )

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
Technique:
- Name: Process Injection
- ID: T1055
- Reference URL: https://attack.mitre.org/techniques/T1055/
Sub-technique:
- Name: Dynamic-link Library Injection
- ID: T1055.001
- Reference URL: https://attack.mitre.org/techniques/T1055/001/
Sub-technique:
- Name: Portable Executable Injection
- ID: T1055.002
- Reference URL: https://attack.mitre.org/techniques/T1055/002/
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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