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The following analytic identifies potential DNS exfiltration using the nslookup application. It detects specific command-line parameters such as query type (TXT, A, AAAA) and retry options, which are commonly used by attackers to exfiltrate data. The detection leverages Endpoint Detection and Response (EDR) telemetry, focusing on process execution logs. This activity is significant as it may indicate an attempt to communicate with a Command and Control (C2) server or exfiltrate sensitive data. If confirmed malicious, this could lead to data breaches and unauthorized access to critical information.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-05-19
  • Author: Teoderick Contreras, Splunk
  • ID: 2452e632-9e0d-11eb-bacd-acde48001122




ID Technique Tactic
T1048 Exfiltration Over Alternative Protocol Exfiltration
Kill Chain Phase
  • Actions On Objectives
  • DE.CM
  • CIS 10
| tstats `security_content_summariesonly` values(Processes.process) as process values(Processes.process_id) as process_id values(Processes.parent_process) as parent_process count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name = "nslookup.exe" Processes.process = "*-querytype=*" OR Processes.process="*-qt=*" OR Processes.process="*-q=*" OR Processes.process="-type=*" OR Processes.process="*-retry=*" by Processes.dest Processes.user Processes.process_name Processes.process Processes.parent_process_name  
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `dns_exfiltration_using_nslookup_app_filter`


The SPL above uses the following Macros:

:information_source: dns_exfiltration_using_nslookup_app_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.

  • _time
  • Processes.dest
  • Processes.user
  • Processes.parent_process_name
  • Processes.parent_process
  • Processes.original_file_name
  • Processes.process_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_path
  • Processes.process_path
  • 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

admin nslookup usage

Associated Analytic Story


Risk Score Impact Confidence Message
72.0 90 80 An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ performing activity related to DNS exfiltration.

: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.


Test Dataset

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