Windows Modify Registry NoChangingWallPaper

name: Windows Modify Registry NoChangingWallPaper
id: a2276412-e254-4e9a-9082-4d92edb6a3e0
version: 12
creation_date: '2024-01-10'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: The following analytic detects modifications to the Windows registry aimed at preventing wallpaper changes. It leverages data from the Endpoint.Registry datamodel, specifically monitoring changes to the "NoChangingWallPaper" registry value. This activity is significant as it is a known tactic used by Rhysida ransomware to enforce a malicious wallpaper, thereby limiting user control over system settings. If confirmed malicious, this registry change could indicate a ransomware infection, leading to further system compromise and user disruption.
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= "*\\Windows\\CurrentVersion\\Policies\\ActiveDesktop\\NoChangingWallPaper" Registry.registry_value_data = 1) 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)` | where isnotnull(registry_value_data) | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_modify_registry_nochangingwallpaper_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, however is not common. Filter as needed.
references:
    - https://www.cisa.gov/news-events/cybersecurity-advisories/aa23-319a
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 ("$dest$") | 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: 7d
      latest_offset: "0"
finding:
    title: the registry settings was modified to disable changing of wallpaper on $dest$.
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - Rhysida Ransomware
asset_type: Endpoint
mitre_attack_id:
    - T1112
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1112/no_changing_wallpaper/NoChangingWallPaper.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit