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Description

This analytic is to detect a suspicious dxdiag.exe process command-line execution. Dxdiag is used to collect the system info of the target host. This technique has been used by Remcos RATS, various actors, and other malware to collect information as part of the recon or collection phase of an attack. This behavior should rarely be seen in a corporate network, but this command line can be used by a network administrator to audit host machine specifications. Thus in some rare cases, this detection will contain false positives in its results. To triage further, analyze what commands were passed after it pipes out the result to a file for further processing.

  • Type: Hunting
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-11-19
  • Author: Teoderick Contreras, Splunk
  • ID: f92d74f2-4921-11ec-b685-acde48001122

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1592 Gather Victim Host Information Reconnaissance
Kill Chain Phase
  • Reconnaissance
NIST
  • DE.AE
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 `process_dxdiag` AND Processes.process = "* /t *" by Processes.dest Processes.user Processes.parent_process_name 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)` 
| `system_info_gathering_using_dxdiag_application_filter`

Macros

The SPL above uses the following Macros:

:information_source: system_info_gathering_using_dxdiag_application_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

To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Processes and Filesystem node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.

Known False Positives

This commandline can be used by a network administrator to audit host machine specifications. Thus, a filter is needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
25.0 50 50 dxdiag.exe process with commandline $process$ on $dest$

: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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