Windows Unusual Intelliform Storage Registry Access

SPLUNK detection rule by Teoderick Contreras, Splunk · Apache-2.0

The following analytic identifies processes accessing Intelliform Storage Registry keys used by Internet Explorer. It leverages Windows Security Event logs, specifically monitoring EventCode 4663, which tracks object access events. This activity is significant because it can indicate unauthorized access or manipulation of sensitive registry keys used for storing form data in Internet Explorer. If confirmed malicious, this could lead to data exfiltration, credential theft, or further compromise of the system.

name: Windows Unusual Intelliform Storage Registry Access
id: 99d69078-7dae-4ffe-9f3d-063242772f5a
version: 5
creation_date: '2025-07-16'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic identifies processes accessing Intelliform Storage Registry keys used by Internet Explorer. It leverages Windows Security Event logs, specifically monitoring EventCode 4663, which tracks object access events. This activity is significant because it can indicate unauthorized access or manipulation of sensitive registry keys used for storing form data in Internet Explorer. If confirmed malicious, this could lead to data exfiltration, credential theft, or further compromise of the system.
data_source:
    - Windows Event Log Security 4663
search: '`wineventlog_security` EventCode=4663  NOT (ProcessName IN("C:\\Program Files\\Internet Explorer\\iexplore.exe", "C:\\Windows\\System32\\dllhost.exe", "C:\\Windows\\SysWow64\\dllhost.exe")) ObjectName IN ("*Software\\microsoft\\Internet Explorer\\Intelliforms\\storage2*") | stats count min(_time) as firstTime max(_time) as lastTime by  ObjectName ObjectType ProcessName AccessMask process_id EventCode Computer Caller_User_Name | rename Computer as dest Caller_User_Name as user ProcessName as process_name |  `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_unusual_intelliform_storage_registry_access_filter`'
how_to_implement: To successfully implement this search, you must ingest Windows Security Event logs and track event code 4663. For 4663, enable "Audit Object Access" in Group Policy. Then check the two boxes listed for both "Success" and "Failure."
known_false_positives: a third party application can access the FileZilla XML config files. Filter is needed.
references:
    - https://stackoverflow.com/questions/1276700/where-does-internet-explorer-stores-its-form-data-history-that-is-uses-for-auto
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"
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: a non Internet Explorer process $process_name$ with $process_id$ accessed Intelliform Storage Registry keys on host $dest$
threat_objects:
    - field: process_name
      type: process_name
analytic_story:
    - Quasar RAT
    - Lokibot
asset_type: Endpoint
mitre_attack_id:
    - T1552.001
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/T1552.001/ie_intelliform_storage/storage2_sim.log
          source: XmlWinEventLog:Security
          sourcetype: XmlWinEventLog
      test_type: unit

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9ec7430e-355e-4c18-a9c7-7b9aecd203b6

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