Windows Proxy Via Registry

name: Windows Proxy Via Registry
id: 0270455b-1385-4579-9ac5-e77046c508ae
version: 10
date: '2026-03-10'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
data_source:
    - Sysmon EventID 13
description: The following analytic detects the modification of registry keys related to the Windows Proxy settings via netsh.exe. It leverages data from the Endpoint.Registry data model, focusing on changes to the registry path "*\\System\\CurrentControlSet\\Services\\PortProxy\\v4tov4\\tcp*". This activity is significant because netsh.exe can be used to establish a persistent proxy, potentially allowing an attacker to execute a helper DLL whenever netsh.exe runs. If confirmed malicious, this could enable the attacker to maintain persistence, manipulate network configurations, and potentially exfiltrate data or further compromise the system.
search: '| tstats `security_content_summariesonly` count  min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Registry where Registry.registry_path ="*\\System\\CurrentControlSet\\Services\\PortProxy\\v4tov4\\tcp*" by Registry.action Registry.dest Registry.process_guid Registry.process_id Registry.registry_hive Registry.registry_path Registry.registry_key_name Registry.registry_value_data Registry.registry_value_name Registry.registry_value_type Registry.status Registry.user Registry.vendor_product | `security_content_ctime(lastTime)` | `security_content_ctime(firstTime)` | `drop_dm_object_name(Registry)` | `windows_proxy_via_registry_filter`'
how_to_implement: To successfully implement this search, you need to be ingesting logs with the registry value name, registry path, and registry value data from your endpoints. If you are using Sysmon, you must have at least version 2.0 of the official Sysmon TA. https://splunkbase.splunk.com/app/5709
known_false_positives: No false positives have been identified at this time.
references:
    - https://www.microsoft.com/en-us/security/blog/2023/05/24/volt-typhoon-targets-us-critical-infrastructure-with-living-off-the-land-techniques/
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168  | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
rba:
    message: A registry modification for port proxy in$dest$
    risk_objects:
        - field: dest
          type: system
          score: 20
    threat_objects: []
tags:
    analytic_story:
        - Volt Typhoon
    asset_type: Endpoint
    atomic_guid:
        - b8223ea9-4be2-44a6-b50a-9657a3d4e72a
    mitre_attack_id:
        - T1090.001
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1090.001/netsh_portproxy/volt_sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog