Windows: Alert on Suspicious Child Processes Spawned by provlaunch.exe

Detects provlaunch.exe launching suspicious child executables and processes from common temp/task paths on Windows.

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windows-alert-on-suspicious-child-processes-spawned-by-provlaunch-exe-f9999590

title: "Windows: Alert on Suspicious Child Processes Spawned by provlaunch.exe"
id: a760d141-6b62-41f5-9d62-3988d8116e63
related:
  - id: 7f5d1c9a-3e83-48df-95a7-2b98aae6c13c
    type: similar
  - id: 2a4b3e61-9d22-4e4a-b60f-6e8f0cde6f25
    type: similar
  - id: 7021255e-5db3-4946-a8b9-0ba7a4644a69
    type: similar
  - id: f9999590-1f94-4a34-a91e-951e47bedefd
    type: derived
status: test
description: This rule flags when provlaunch.exe spawns specific child processes commonly abused for execution and scripting, including calc.exe, cmd.exe, cscript.exe, mshta.exe, notepad.exe, powershell.exe/pwsh.exe, regsvr32.exe, rundll32.exe, and wscript.exe. It also catches cases where the spawned process command path includes typical staging or task locations such as PerfLogs, Temp, Users\Public, AppData\Temp, and Windows\Tasks/Temp. This matters because attackers may use provlaunch.exe to proxy execution and move into more capable tooling or script interpreters, which is observable via process creation telemetry on Windows.
references:
  - https://lolbas-project.github.io/lolbas/Binaries/Provlaunch/
  - https://twitter.com/0gtweet/status/1674399582162153472
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_provlaunch_susp_child_process.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2023-08-08
tags:
  - attack.stealth
  - attack.t1218
logsource:
  category: process_creation
  product: windows
detection:
  selection_parent:
    ParentImage|endswith: \provlaunch.exe
  selection_child:
    - Image|endswith:
        - \calc.exe
        - \cmd.exe
        - \cscript.exe
        - \mshta.exe
        - \notepad.exe
        - \powershell.exe
        - \pwsh.exe
        - \regsvr32.exe
        - \rundll32.exe
        - \wscript.exe
    - Image|contains:
        - :\PerfLogs\
        - :\Temp\
        - :\Users\Public\
        - \AppData\Temp\
        - \Windows\System32\Tasks\
        - \Windows\Tasks\
        - \Windows\Temp\
  condition: all of selection_*
falsepositives:
  - Unknown
level: high
license: DRL-1.1

What it detects

This rule flags when provlaunch.exe spawns specific child processes commonly abused for execution and scripting, including calc.exe, cmd.exe, cscript.exe, mshta.exe, notepad.exe, powershell.exe/pwsh.exe, regsvr32.exe, rundll32.exe, and wscript.exe. It also catches cases where the spawned process command path includes typical staging or task locations such as PerfLogs, Temp, Users\Public, AppData\Temp, and Windows\Tasks/Temp. This matters because attackers may use provlaunch.exe to proxy execution and move into more capable tooling or script interpreters, which is observable via process creation telemetry on Windows.

Known false positives

Unknown

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.