Windows Process Creation: Suspicious Child Processes Spawned by regsvr32.exe

Alerts when regsvr32.exe spawns suspicious child processes like PowerShell, mshta, or scripting utilities.

FreeReviewedSigma · High · v1

Product: windows
Category: process_creation
Author: elhoim, Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2022-05-05
Updated: 2026-07-30

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218.010Regsvr32
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags process creation events where the parent process is regsvr32.exe and the child process image matches a set of common interactive or scripting tools. Such behavior matters because regsvr32.exe can be abused to load and execute code via child processes, blending execution into normal-looking Windows activity. The detection relies on Windows process creation telemetry, specifically parent image and child image (with an exclusion for werfault.exe launched with a particular command-line pattern).

Reporting behind it

Related detections9 linkedT1218.010 — drag to rearrange

Malicious Regsvr32 ShellExec_RunDLL Proxy Execution (via process_creation)

Suspicious DLL Execution via Regsvr32 DllInstall of dat File

Malicious Xctdoor XcLoader Execution via Regsvr32 AppX Path Abuse (via process_creation)

Malicious Office Application Loading a User-Path DLL via Regsvr32 or Rundll32 (via process_creation)

Masquerading SSLoad PhantomLoader DLL Execution via Regsvr32 Silent Load from AppData (via process_creation)

Malicious Kimsuky AlphaSeed Payload Execution via Regsvr32 Loading edge dat (via process_creation)

Malicious Regsvr32 Executing DLL From Windows Temp

HttpSpy Payload Registration via Regsvr32 of Non-DLL File (via process_creation)

Malicious regsvr32 Scriptlet Execution via scrobj.dll

Windows Process Creation: Suspicious Child Processes Spawned by regsvr32.exe

Pivot detection · T1218.010 · 9 related

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

windows-process-creation-suspicious-child-processes-spawned-by-regsvr32-exe-6f0947a4

title: "Windows Process Creation: Suspicious Child Processes Spawned by regsvr32.exe"
id: 3baf4508-dca1-43c0-89b3-3a40c9aea588
related:
  - id: 8e2b24c9-4add-46a0-b4bb-0057b4e6187d
    type: obsolete
  - id: 6f0947a4-1c5e-4e0d-8ac7-53159b8f23ca
    type: derived
status: test
description: This rule flags process creation events where the parent process is regsvr32.exe and the child process image matches a set of common interactive or scripting tools. Such behavior matters because regsvr32.exe can be abused to load and execute code via child processes, blending execution into normal-looking Windows activity. The detection relies on Windows process creation telemetry, specifically parent image and child image (with an exclusion for werfault.exe launched with a particular command-line pattern).
references:
  - https://redcanary.com/blog/intelligence-insights-april-2022/
  - https://www.echotrail.io/insights/search/regsvr32.exe
  - https://www.ired.team/offensive-security/code-execution/t1117-regsvr32-aka-squiblydoo
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_regsvr32_susp_child_process.yml
author: elhoim, Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-05-05
modified: 2023-05-26
tags:
  - attack.stealth
  - attack.t1218.010
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    ParentImage|endswith: \regsvr32.exe
    Image|endswith:
      - \calc.exe
      - \cscript.exe
      - \explorer.exe
      - \mshta.exe
      - \net.exe
      - \net1.exe
      - \nltest.exe
      - \notepad.exe
      - \powershell.exe
      - \pwsh.exe
      - \reg.exe
      - \schtasks.exe
      - \werfault.exe
      - \wscript.exe
  filter_main_werfault:
    Image|endswith: \werfault.exe
    CommandLine|contains: " -u -p "
  condition: selection and not 1 of filter_main_*
falsepositives:
  - Unlikely, but can rarely occur. Apply additional filters accordingly.
level: high
license: DRL-1.1

Convert

This rule as a query you can run. Uses no unlock credit.

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