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Detection rules › Sigma

Suspicious ArcSOC.exe Child Process

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

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.

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059 Command and Scripting Interpreter, T1203 Exploitation for Client Execution

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation
Security-AuditingEvent ID 4688A new process has been created.

Rule body yaml

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

Stages and Predicates

Stage 0: condition

selection and not 1 of filter_main_*

Stage 1: selection

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'

Stage 2: not filter_main_cmd

filter_main_cmd:
    Image|endswith: '\cmd.exe'
    CommandLine: 'cmd.exe /c "ver"'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
CommandLineeqcmd.exe /c "ver"
Imageends_with\cmd.exe

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
  • \cmd.exe corpus 130 (sigma 130)
  • \cscript.exe corpus 73 (sigma 73)
  • \mshta.exe corpus 67 (sigma 67)
  • \powershell.exe corpus 182 (sigma 182)
  • \pwsh.exe corpus 168 (sigma 168)
  • \regsvr32.exe corpus 65 (sigma 65)
  • \rundll32.exe corpus 95 (sigma 95)
  • \wmic.exe corpus 60 (sigma 60)
  • \wscript.exe corpus 75 (sigma 75)
ParentImageends_with
  • \ArcSOC.exe