Detection rules › Sigma

Suspicious File Created by ArcSOC.exe

Status
experimental
Severity
high
Log source
product windows, category file_event
Author
Micah Babinski
Source
github.com/SigmaHQ/sigma

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.

MITRE ATT&CK coverage

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

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

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith: '\ArcSOC.exe'
    TargetFilename|endswith:
        - '.ahk'
        - '.aspx'
        - '.au3'
        - '.bat'
        - '.cmd'
        - '.dll'
        - '.exe'
        - '.hta'
        - '.js'
        - '.ps1'
        - '.py'
        - '.vbe'
        - '.vbs'
        - '.wsf'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Imageends_with
  • \ArcSOC.exe
TargetFilenameends_with
  • .ahk
  • .aspx corpus 5 (sigma 5)
  • .au3 corpus 2 (sigma 2)
  • .bat corpus 17 (sigma 17)
  • .cmd corpus 8 (sigma 8)
  • .dll corpus 23 (sigma 23)
  • .exe corpus 21 (sigma 20, splunk 1)
  • .hta corpus 13 (sigma 13)
  • .js corpus 9 (sigma 9)
  • .ps1 corpus 17 (sigma 17)
  • .py corpus 2 (sigma 2)
  • .vbe corpus 15 (sigma 15)
  • .vbs corpus 18 (sigma 18)
  • .wsf corpus 7 (sigma 7)