Registry Keys for Creating SHIM Databases

SPLUNK detection rule by Patrick Bareiss, Teoderick Contreras, Splunk, Steven Dick, Bhavin Patel · Apache-2.0

The following analytic detects registry activity related to the creation of application compatibility shims. It leverages data from the Endpoint.Registry data model, specifically monitoring registry paths associated with AppCompatFlags. This activity is significant because attackers can use shims to bypass security controls, achieve persistence, or escalate privileges. If confirmed malicious, this could allow an attacker to maintain long-term access, execute arbitrary code, or manipulate application behavior, posing a severe risk to the integrity and security of the affected systems.

name: Registry Keys for Creating SHIM Databases
id: f5f6af30-7aa7-4295-bfe9-07fe87c01bbb
version: 17
creation_date: '2020-04-29'
modification_date: '2026-05-13'
author: Patrick Bareiss, Teoderick Contreras, Splunk, Steven Dick, Bhavin Patel
status: production
type: TTP
description: The following analytic detects registry activity related to the creation of application compatibility shims. It leverages data from the Endpoint.Registry data model, specifically monitoring registry paths associated with AppCompatFlags. This activity is significant because attackers can use shims to bypass security controls, achieve persistence, or escalate privileges. If confirmed malicious, this could allow an attacker to maintain long-term access, execute arbitrary code, or manipulate application behavior, posing a severe risk to the integrity and security of the affected systems.
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=*CurrentVersion\\AppCompatFlags\\Custom* OR Registry.registry_path=*CurrentVersion\\AppCompatFlags\\InstalledSDB*) 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)` | `registry_keys_for_creating_shim_databases_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: There are many legitimate applications that leverage shim databases for compatibility purposes for legacy applications
references: []
drilldown_searches:
    - name: View the detection results for - "$dest$" and "$user$"
      search: '%original_detection_search% | search  dest = "$dest$" user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$" and "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$", "$user$") | 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: A registry activity in $registry_path$ related to shim modication in host $dest$
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: A registry activity in $registry_path$ related to shim modication in host $dest$
analytic_story:
    - Suspicious Windows Registry Activities
    - Windows Persistence Techniques
    - Windows Registry Abuse
asset_type: Endpoint
mitre_attack_id:
    - T1546.011
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/T1546.011/atomic_red_team/windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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4c749782-a03c-4f32-ab6c-c2e1c8cea095

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