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Description

The following analytic identifies the Windows Explorer process with a URL within the command-line. Explorer.exe is known Windows process that handles start menu, taskbar, desktop and file manager. Many adversaries abuse this process, like DCRat malware, where it attempts to open the URL with the default browser application on the target host by putting the URL as a parameter on explorer.exe process. This anomaly detection might be a good pivot to check which user and how this process was executed, what is the parent process and what is the URL link. This technique is not commonly used to open an URL.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2022-08-30
  • Author: Teoderick Contreras, Splunk
  • ID: 76753bab-f116-4ea3-8fb9-89b638be58a9

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1105 Ingress Tool Transfer Command And Control
Kill Chain Phase
  • Command and Control
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


1
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| 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.parent_process_name Processes.parent_process Processes.process_name Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id Processes.dest Processes.user 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_ingress_tool_transfer_using_explorer_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_ingress_tool_transfer_using_explorer_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

False positives may be present based on legitimate applications or third party utilities. Filter out any additional parent process names.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
25.0 50 50 An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ attempting to download a remote payload.

: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

source | version: 2