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Description

The following analytic detects the creation or deletion of hidden shares using the net.exe command for prompt response and mitigation to enhance the overall security posture of the organization and protect against potential data breaches, malware infections, and other damaging outcomes. This detection is made by searching for processes that involve the use of net.exe and filters for actions related to creation or deletion of shares. This detection is important because it suggests that an attacker is attempting to manipulate or exploit the network by creating or deleting hidden shares. The creation or deletion of hidden shares can indicate malicious activity since attackers might use hidden shares to exfiltrate data, distribute malware, or establish persistence within a network. The impact of such an attack can vary, but it often involves unauthorized access to sensitive information, disruption of services, or the introduction of malware. False positives might occur since legitimate actions can also involve the use of net.exe. An extensive triage and investigation is necessary to determine the intent and nature of the detected activity. Next steps include reviewing the details of the process involving the net.exe command, including the user, parent process, and timestamps during the triage. Additionally, capture and inspect any relevant on-disk artifacts and review concurrent processes to identify the source of the attack.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2020-09-16
  • Author: Bhavin Patel, Splunk
  • ID: 743a322c-9a68-4a0f-9c17-85d9cce2a27c

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1070 Indicator Removal Defense Evasion
T1070.005 Network Share Connection Removal Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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| tstats `security_content_summariesonly` count values(Processes.user) as user values(Processes.parent_process) as parent_process min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_net` by Processes.process Processes.process_name  Processes.parent_process_name Processes.original_file_name Processes.dest 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` 
| search process=*share* 
| `create_or_delete_windows_shares_using_net_exe_filter`

Macros

The SPL above uses the following Macros:

:information_source: create_or_delete_windows_shares_using_net_exe_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

Administrators often leverage net.exe to create or delete network shares. You should verify that the activity was intentional and is legitimate.

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 $user$ enumerating Windows file shares.

: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: 6