Suspicious File Created by ArcSOC.exe — Sigma Rule

Rule metadata and linked tags

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

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 3a0b40423e33d2097c98dac888a3162857e995314ad57dd2b40250a0a4814c6d

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 File Created by ArcSOC.exe
id: e890acee-d488-420e-8f20-d9b19b3c3d43
status: experimental
description: |
    Detects instances where the ArcGIS Server process ArcSOC.exe, which hosts REST services running on an ArcGIS
    server, creates a file with suspicious file type, indicating that it may be an executable, script file,
    or otherwise unusual.
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.command-and-control
    - attack.persistence
    - attack.initial-access
    - attack.execution
    - attack.stealth
    - attack.t1127
    - attack.t1105
    - attack.t1133
logsource:
    category: file_event
    product: windows
detection:
    selection:
        Image|endswith: '\ArcSOC.exe'
        TargetFilename|endswith:
            - '.ahk'
            - '.aspx'
            - '.au3'
            - '.bat'
            - '.cmd'
            - '.dll'
            - '.exe'
            - '.hta'
            - '.js'
            - '.ps1'
            - '.py'
            - '.vbe'
            - '.vbs'
            - '.wsf'
    condition: selection
falsepositives:
    - Unlikely
level: high

Original YAML and metadata in JSON

False positives

• Unlikely

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