Windows ConHost with Headless Argument

SPLUNK detection rule by Michael Haag, Splunk · Apache-2.0

The following analytic detects the unusual invocation of the Windows Console Host process (conhost.exe) with the undocumented --headless parameter. This detection leverages Endpoint Detection and Response (EDR) telemetry, specifically monitoring for command-line executions where conhost.exe is executed with the --headless argument. This activity is significant for a SOC as it is not commonly used in legitimate operations and may indicate an attacker's attempt to execute commands stealthily. If confirmed malicious, this behavior could lead to persistence, lateral movement, or other malicious activities, potentially resulting in data exfiltration or system compromise.

name: Windows ConHost with Headless Argument
id: d5039508-998d-4cfc-8b5e-9dcd679d9a62
version: 11
creation_date: '2023-11-16'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic detects the unusual invocation of the Windows Console Host process (conhost.exe) with the undocumented --headless parameter. This detection leverages Endpoint Detection and Response (EDR) telemetry, specifically monitoring for command-line executions where conhost.exe is executed with the --headless argument. This activity is significant for a SOC as it is not commonly used in legitimate operations and may indicate an attacker's attempt to execute commands stealthily. If confirmed malicious, this behavior could lead to persistence, lateral movement, or other malicious activities, potentially resulting in data exfiltration or system compromise.
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_name=conhost.exe Processes.process="*--headless *"
      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_conhost_with_headless_argument_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 if the application is legitimately used, filter by user or endpoint as needed.
references:
    - https://x.com/embee_research/status/1559410767564181504?s=20
    - https://x.com/GroupIB_TI/status/1719675754886131959?s=20
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"
finding:
    title: Windows ConHost with Headless Argument detected on $dest$ by $user$.
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: Windows ConHost with Headless Argument detected on $dest$ by $user$.
analytic_story:
    - Spearphishing Attachments
    - Compromised Windows Host
asset_type: Endpoint
mitre_attack_id:
    - T1564.003
    - T1564.006
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/T1564.003/headless/4688_conhost_headless.log
          source: XmlWinEventLog:Security
          sourcetype: XmlWinEventLog
      test_type: unit

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