Uncommon ADWS (Port 9389) Connections from Non-Standard Windows Binaries

Alerts on unexpected process-to-ADWS (TCP/9389) connections on Windows to highlight potential directory discovery.

FreeReviewedSigma · Medium · v2
Product
windows
Category
network_connection
Author
@kostastsale (SigmaHQ), DRL 1.1
Published
2024-01-26
Updated
2026-07-31
title: Uncommon ADWS (Port 9389) Connections from Non-Standard Windows Binaries
id: 35cf1576-467b-43b2-aa74-69cd88743748
status: test
description: This rule flags network connections to Active Directory Web Services using TCP port 9389 when the initiating process is not one of the expected ADWS management binaries. Attackers may use ADWS to query or discover Active Directory data, so uncommon process-to-ADWS communication can indicate misuse. The rule relies on Windows network connection telemetry (destination port and initiated connection) and process image path context to identify unexpected callers.
references:
  - https://medium.com/falconforce/soaphound-tool-to-collect-active-directory-data-via-adws-165aca78288c
  - https://github.com/FalconForceTeam/FalconFriday/blob/a9219dfcfd89836f34660223f47d766982bdce46/Discovery/ADWS_Connection_from_Unexpected_Binary-Win.md
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/network_connection/net_connection_win_adws_unusual_connection.yml
author: "@kostastsale, Huntrule Team"
date: 2024-01-26
tags:
  - attack.discovery
  - attack.t1087
logsource:
  category: network_connection
  product: windows
detection:
  selection:
    Initiated: true
    DestinationPort: 9389
  filter_main_dsac:
    Image: C:\Windows\system32\dsac.exe
  filter_main_ms_monitoring_agent:
    Image: C:\Program Files\Microsoft Monitoring Agent\
  filter_main_powershell:
    Image|startswith:
      - C:\Program Files\PowerShell\7\pwsh.exe
      - C:\Program Files\PowerShell\7-preview\pwsh.ex
      - C:\Windows\System32\WindowsPowerShell\
      - C:\Windows\SysWOW64\WindowsPowerShell\
  condition: selection and not 1 of filter_main_*
falsepositives:
  - ADWS is used by a number of legitimate applications that need to interact with Active Directory. These applications should be added to the allow-listing to avoid false positives.
level: medium
license: DRL-1.1
related:
  - id: b3ad3c0f-c949-47a1-a30e-b0491ccae876
    type: derived