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Description

The following analytic detects the unusual use of the Windows Console Host process (conhost.exe) with the undocumented –headless parameter to spawn a new process. This behavior is highly unusual and indicative of suspicious activity, as the –headless parameter is not commonly used in legitimate operations. The analytic identifies this behavior by looking for instances where conhost.exe is invoked with the –headless argument. This behavior is worth identifying for a Security Operations Center (SOC) as it could indicate an attacker's attempt to execute commands or scripts in a stealthy manner, potentially to establish persistence, perform lateral movement, or carry out other malicious activities. If a true positive is identified, it suggests that an attacker has gained a foothold in the environment and is attempting to further their attack, which could lead to serious consequences such as data exfiltration, system compromise, or deployment of ransomware. Potential false positives could arise from legitimate administrative activity, hence it is important to validate the context of the detected behavior during triage.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2023-11-01
  • Author: Michael Haag, Splunk
  • ID: d5039508-998d-4cfc-8b5e-9dcd679d9a62

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1564.003 Hidden Window Defense Evasion
T1564.006 Run Virtual Instance Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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| 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.dest Processes.user Processes.parent_process Processes.process_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_conhost_with_headless_argument_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_conhost_with_headless_argument_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • Processes.dest
  • Processes.user
  • Processes.parent_process
  • Processes.process_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_id

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.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
70.0 100 70 Windows ConHost with Headless Argument detected on $dest$ by $user$.

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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