Suspicious ArcSOC.exe Child Process — Sigma Rule

Rule metadata and linked tags

Author: Micah Babinski. Source status: experimental; severity: high. Source dates: 2025-11-25 / not supplied.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 0d69f0aad73732e5af619707a42d0013c6fb08cae11905b5c6bc4f315f04f5cb

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Suspicious ArcSOC.exe Child Process
id: 8e95e73e-ba02-4a87-b4d7-0929b8053038
status: experimental
description: |
    Detects script interpreters, command-line tools, and similar suspicious child processes of ArcSOC.exe.
    ArcSOC.exe is the process name which hosts ArcGIS Server REST services. If an attacker compromises an ArcGIS
    Server system and uploads a malicious Server Object Extension (SOE), they can send crafted requests to the corresponding
    service endpoint and remotely execute code from the ArcSOC.exe process.
references:
    - https://reliaquest.com/blog/threat-spotlight-inside-flax-typhoons-arcgis-compromise/
    - https://enterprise.arcgis.com/en/server/12.0/administer/windows/inside-an-arcgis-server-site.htm
author: Micah Babinski
date: 2025-11-25
tags:
    - attack.execution
    - attack.t1059
    - attack.t1203
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\ArcSOC.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\cscript.exe'
            - '\mshta.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\regsvr32.exe'
            - '\rundll32.exe'
            - '\wmic.exe'
            - '\wscript.exe'
    filter_main_cmd:
        Image|endswith: '\cmd.exe'
        CommandLine: 'cmd.exe /c "ver"'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://reliaquest.com/blog/threat-spotlight-inside-flax-typhoons-arcgis-compromise/
• https://enterprise.arcgis.com/en/server/12.0/administer/windows/inside-an-arcgis-server-site.htm