Detection rules › Splunk
Windows Modify Registry Disable RDP
This analytic is developed to detect suspicious registry modifications that disable Remote Desktop Protocol (RDP) by altering the "fDenyTSConnections" key. Changing this key's value to 1 prevents remote connections, which can disrupt remote management and access. Such modifications could indicate an attempt to hinder remote administration or isolate the system from remote intervention, potentially signifying malicious activity.
Known false positives
- administrators may enable or disable this feature that may cause some false positive.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence | |
| Defense Impairment |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 13: RegistryEvent (Value Set) |
Rule body
name: Windows Modify Registry Disable RDP
id: 11ed764f-eb9c-4be7-bdad-2209b9d33ee1
version: 10
creation_date: '2024-07-25'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: This analytic is developed to detect suspicious registry modifications that disable Remote Desktop Protocol (RDP) by altering the "fDenyTSConnections" key. Changing this key's value to 1 prevents remote connections, which can disrupt remote management and access. Such modifications could indicate an attempt to hinder remote administration or isolate the system from remote intervention, potentially signifying malicious activity.
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= "*\\Control\\Terminal Server\\fDenyTSConnections*" 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_disable_rdp_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 `Processes` node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
known_false_positives: administrators may enable or disable this feature that may cause some false positive.
references:
- https://www.bleepingcomputer.com/news/security/new-shrinklocker-ransomware-uses-bitlocker-to-encrypt-your-files/
intermediate_findings:
entities:
- field: dest
type: system
score: 20
message: A registry modification in Windows RDP registry settings on $dest$
analytic_story:
- ShrinkLocker
- Windows RDP Artifacts and Defense Evasion
asset_type: Endpoint
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= "*\\Control\\Terminal Server\\fDenyTSConnections*" 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_disable_rdp_filter`
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
Registry.registry_path | eq |
| field:"registry_path" kind:eq |
Registry.registry_value_data | eq |
| field:"Details" kind:eq |