Windows Registry Payload Injection

SPLUNK detection rule by Steven Dick · Apache-2.0

The following analytic detects suspiciously long data written to the Windows registry, a behavior often linked to fileless malware or persistence techniques. It leverages Endpoint Detection and Response (EDR) telemetry, focusing on registry events with data lengths exceeding 512 characters. This activity is significant as it can indicate an attempt to evade traditional file-based defenses, making it crucial for SOC monitoring. If confirmed malicious, this technique could allow attackers to maintain persistence, execute code, or manipulate system configurations without leaving a conventional file footprint.

name: Windows Registry Payload Injection
id: c6b2d80f-179a-41a1-b95e-ce5601d7427a
version: 13
creation_date: '2023-07-11'
modification_date: '2026-05-13'
author: Steven Dick
status: production
type: TTP
description: The following analytic detects suspiciously long data written to the Windows registry, a behavior often linked to fileless malware or persistence techniques. It leverages Endpoint Detection and Response (EDR) telemetry, focusing on registry events with data lengths exceeding 512 characters. This activity is significant as it can indicate an attempt to evade traditional file-based defenses, making it crucial for SOC monitoring. If confirmed malicious, this technique could allow attackers to maintain persistence, execute code, or manipulate system configurations without leaving a conventional file footprint.
data_source:
    - Sysmon EventID 13
search: |-
    | tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Registry
      WHERE Registry.registry_value_data=*
      BY _time span=1h Registry.dest
         Registry.registry_path Registry.registry_value_name Registry.process_guid
         Registry.registry_value_data Registry.registry_key_name Registry.registry_hive
         Registry.status Registry.action Registry.process_id
         Registry.user Registry.vendor_product
    | `drop_dm_object_name(Registry)`
    | eval reg_data_len = len(registry_value_data)
    | where reg_data_len > 512
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_registry_payload_injection_filter`
how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
known_false_positives: No false positives have been identified at this time.
references:
    - https://www.mandiant.com/resources/blog/tracking-evolution-gootloader-operations
    - https://www.trendmicro.com/vinfo/us/security/news/cybercrime-and-digital-threats/kovter-an-evolving-malware-gone-fileless
    - https://attack.mitre.org/techniques/T1027/011/
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: A process added a suspicious length of registry data on $dest$.
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - Unusual Processes
asset_type: Endpoint
mitre_attack_id:
    - T1027.011
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/malware/gootloader/partial_ttps/windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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