Windows Ingress Tool Transfer Using Explorer

name: Windows Ingress Tool Transfer Using Explorer
id: 76753bab-f116-4ea3-8fb9-89b638be58a9
version: 14
creation_date: '2022-08-01'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic identifies instances where the Windows Explorer process (explorer.exe) is executed with a URL in its command line. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution logs. This activity is significant because adversaries, such as those using DCRat malware, may abuse explorer.exe to open URLs with the default browser, which is an uncommon and suspicious behavior. If confirmed malicious, this technique could allow attackers to download and execute malicious payloads, leading to potential system compromise and further malicious activities.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |
    | tstats `security_content_summariesonly` min(_time) as firstTime max(_time)
    as lastTime from datamodel=Endpoint.Processes where
    (Processes.process_name = explorer.exe OR Processes.original_file_name = explorer.exe)
    AND NOT (Processes.parent_process_name IN("userinit.exe", "svchost.exe"))
    Processes.process IN ("* http://*", "* https://*")
    by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
    Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
    Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec
    Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level
    Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product
    | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
    | `windows_ingress_tool_transfer_using_explorer_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: False positives may be present based on legitimate applications or third party utilities. Filter out any additional parent process names.
references:
    - https://www.mandiant.com/resources/analyzing-dark-crystal-rat-backdoor
drilldown_searches:
    - name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - 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"
intermediate_findings:
    entities:
        - field: user
          type: user
          score: 20
          message: An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ attempting to download a remote payload.
        - field: dest
          type: system
          score: 20
          message: An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ attempting to download a remote payload.
threat_objects:
    - field: parent_process_name
      type: parent_process_name
    - field: process_name
      type: process_name
analytic_story:
    - DarkCrystal RAT
asset_type: Endpoint
mitre_attack_id:
    - T1105
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/dcrat/dcrat_explorer_url/sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit