Windows Process Creation: Wstomcatservice.exe Parent Spawning Processes (Log4j Wstomcat)

Detects processes spawned by ws_tomcatservice.exe on Windows, excluding repadmin.exe, to surface potential Tomcat exploitation.

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windows-process-creation-wstomcatservice-exe-parent-spawning-processes-log4j-wst-7c97c625

title: "Windows Process Creation: Wstomcatservice.exe Parent Spawning Processes (Log4j Wstomcat)"
id: 3a6b0359-e395-4488-86ab-d12cfb3b6cea
status: test
description: This rule flags Windows process execution where the parent process path ends with \ws_tomcatservice.exe. It matters because activity originating from the Tomcat service can indicate exploitation paths that lead to arbitrary command execution. Detection relies on process creation telemetry that includes parent image and process image paths, and it suppresses events where the spawned process is repadmin.exe. The match focuses on parent image context rather than command-line content.
references:
  - https://www.microsoft.com/en-us/security/blog/2023/04/18/nation-state-threat-actor-mint-sandstorm-refines-tradecraft-to-attack-high-value-targets/
  - https://github.com/SigmaHQ/sigma/blob/master/rules-emerging-threats/2023/TA/Mint-Sandstorm/proc_creation_win_apt_mint_sandstorm_log4j_wstomcat_execution.yml
author: Nasreddine Bencherchali (Nextron Systems), MSTIC (idea), Huntrule Team
date: 2023-04-20
modified: 2023-11-29
tags:
  - attack.execution
  - detection.emerging-threats
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    ParentImage|endswith: \ws_tomcatservice.exe
  filter_main_repadmin:
    Image|endswith: \repadmin.exe
  condition: selection and not 1 of filter_main_*
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: 7c97c625-0350-4f0a-8943-f6cadc88125e
    type: derived

What it detects

This rule flags Windows process execution where the parent process path ends with \ws_tomcatservice.exe. It matters because activity originating from the Tomcat service can indicate exploitation paths that lead to arbitrary command execution. Detection relies on process creation telemetry that includes parent image and process image paths, and it suppresses events where the spawned process is repadmin.exe. The match focuses on parent image context rather than command-line content.

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.