Detection rules › Splunk

Windows Modify Registry EnableLinkedConnections

Status
production
Severity
medium
Group by
TargetObject, computer_name, details, event_type, process_guid, process_id, registry_hive, registry_path, registry_status, registry_value_name, registry_value_type, user, vendor_product
Author
Teoderick Contreras, Splunk
Source
github.com/splunk/security_content

The following analytic detects a suspicious modification to the Windows registry setting for EnableLinkedConnections. It leverages data from the Endpoint.Registry datamodel to identify changes where the registry path is "*\Microsoft\Windows\CurrentVersion\Policies\System\EnableLinkedConnections" and the value is set to "0x00000001". This activity is significant because enabling linked connections can allow network shares to be accessed with both standard and administrator-level privileges, a technique often abused by malware like BlackByte ransomware. If confirmed malicious, this could lead to unauthorized access to sensitive network resources, escalating the attacker's privileges.

Known false positives

  • Administrators may enable or disable this feature that may cause some false positive.

MITRE ATT&CK coverage

TacticTechniques
Persistence
Defense Impairment

Telemetry coverage

Rule body

name: Windows Modify Registry EnableLinkedConnections
id: 93048164-3358-4af0-8680-aa5f38440516
version: 12
creation_date: '2023-07-10'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: The following analytic detects a suspicious modification to the Windows registry setting for EnableLinkedConnections. It leverages data from the Endpoint.Registry datamodel to identify changes where the registry path is "*\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\EnableLinkedConnections" and the value is set to "0x00000001". This activity is significant because enabling linked connections can allow network shares to be accessed with both standard and administrator-level privileges, a technique often abused by malware like BlackByte ransomware. If confirmed malicious, this could lead to unauthorized access to sensitive network resources, escalating the attacker's privileges.
data_source:
    - Sysmon EventID 13
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path= "*\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\EnableLinkedConnections" Registry.registry_value_data = "0x00000001") 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 | `drop_dm_object_name(Registry)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_modify_registry_enablelinkedconnections_filter`'
how_to_implement: To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the `Endpoint` datamodel in the `Registry` node. Also make sure that this registry was included in your config files ex. sysmon config to be monitored.
known_false_positives: Administrators may enable or disable this feature that may cause some false positive.
references:
    - https://www.microsoft.com/en-us/security/blog/2023/07/06/the-five-day-job-a-blackbyte-ransomware-intrusion-case-study/
finding:
    title: A registry modification in Windows EnableLinkedConnections configuration on $dest$
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - BlackByte Ransomware
asset_type: Endpoint
atomic_guid:
    - 4f4e2f9f-6209-4fcf-9b15-3b7455706f5b
mitre_attack_id:
    - T1112
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path= "*\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\EnableLinkedConnections" Registry.registry_value_data = "0x00000001") 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

Stage 2: search

| `drop_dm_object_name(Registry)`

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: search

| `windows_modify_registry_enablelinkedconnections_filter`

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Registry.registry_patheq
  • "*\\Microsoft\\Windows\\CurrentVersion\\Policies\\System\\EnableLinkedConnections"
field:"registry_path" kind:eq
Registry.registry_value_dataeq
  • "0x00000001" corpus 61 (splunk 52, elastic 9)
field:"Details" kind:eq