Detection rules › Splunk

Windows IOBit Unlocker Extension DLL Registration via Regsvr32

Status
production
Severity
medium
Group by
CurrentDirectory, IntegrityLevel, command_line, computer_name, event_action, original_file_name, parent_command_line, parent_process_guid, parent_process_id, parent_process_name, process_guid, process_hash, process_id, process_name, user, user_id, vendor_product
Author
Raven Tait, Splunk
Source
github.com/splunk/security_content

Detects the IOBit Unlocker Extension being registered. IObit Unlocker is a utility designed to resolve issues involving files or folders that cannot be deleted, moved, or renamed due to being locked by other processes or applications in Windows. It's a powerful tool that can "unlock" these files or folders, terminating any processes that are using them. This allows users to manipulate these previously inaccessible files or folders as needed.

MITRE ATT&CK coverage

Event coverage

Rule body splunk

name: Windows IOBit Unlocker Extension DLL Registration via Regsvr32
id: 2ba4b456-76e2-439d-bca6-fd5ef24cc53b
version: 2
creation_date: '2021-12-08'
modification_date: '2026-05-13'
author: Raven Tait, Splunk
status: production
type: TTP
description: |-
    Detects the IOBit Unlocker Extension being registered.
    IObit Unlocker is a utility designed to resolve issues involving files or folders that cannot be deleted, moved, or renamed due to being locked by other processes or applications in Windows.
    It's a powerful tool that can "unlock" these files or folders, terminating any processes that are using them.
    This allows users to manipulate these previously inaccessible files or folders as needed.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |-
    | tstats `security_content_summariesonly`
      count min(_time) as firstTime
            max(_time) as lastTime
    
    from datamodel=Endpoint.Processes where
    
    Processes.process="*IObitUnlockerExtension.dll*"
    Processes.process_name="regsvr32.exe"
    
    by Processes.process Processes.vendor_product Processes.user_id Processes.process_hash
       Processes.parent_process_name Processes.parent_process_exec Processes.action
       Processes.dest Processes.process_current_directory Processes.process_path
       Processes.process_integrity_level Processes.original_file_name Processes.parent_process
       Processes.parent_process_path Processes.parent_process_guid Processes.parent_process_id
       Processes.process_guid Processes.process_id Processes.user Processes.process_name
    
    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_iobit_unlocker_extension_dll_registration_via_regsvr32_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: Some legitimate users may run IObit Unlocker to manage locked files for maintenance or troubleshooting. Filter detections for approved use to reduce false alerts.
references:
    - https://thedfirreport.com/2024/04/01/from-onenote-to-ransomnote-an-ice-cold-intrusion/
drilldown_searches:
    - earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
      name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") | 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: Potential IOBit Unlocker Extension DLL activity observed on $dest$ via $process$.
    entity:
        field: dest
        type: system
        score: 50
threat_objects:
    - field: parent_process_name
      type: parent_process_name
analytic_story:
    - Compromised Windows Host
asset_type: Endpoint
mitre_attack_id:
    - T1218.010
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/T1218.010/snapattack/snapattack.log
          source: XmlWinEventLog:Security
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly`
  count min(_time) as firstTime
        max(_time) as lastTime

from datamodel=Endpoint.Processes where

Processes.process="*IObitUnlockerExtension.dll*"
Processes.process_name="regsvr32.exe"

by Processes.process Processes.vendor_product Processes.user_id Processes.process_hash
   Processes.parent_process_name Processes.parent_process_exec Processes.action
   Processes.dest Processes.process_current_directory Processes.process_path
   Processes.process_integrity_level Processes.original_file_name Processes.parent_process
   Processes.parent_process_path Processes.parent_process_guid Processes.parent_process_id
   Processes.process_guid Processes.process_id Processes.user Processes.process_name

Stage 2: search

| `drop_dm_object_name(Processes)`

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: search

| `windows_iobit_unlocker_extension_dll_registration_via_regsvr32_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Processes.processeq
  • "*IObitUnlockerExtension.dll*"
Processes.process_nameeq
  • "regsvr32.exe" corpus 25 (elastic 19, splunk 6)