windows_system_user_discovery_via_quser.yml

name: Windows System User Discovery Via Quser
id: 0c3f3e09-e47a-410e-856f-a02a5c5fafb0
version: 1
date: '2022-11-30'
author: Teoderick Contreras, Splunk
status: production
type: Hunting
description: The following analytic identifies a process execution of Windows OS quser.exe
  tool. This tool is being abused or used by several post exploitation tool such as
  winpeas that being used by ransomware prestige to display or gather information
  about user sessions on a Remote Desktop Session Host server. This command can find
  out if a specific user is logged on to a specific Remote Desktop Session Host server.
  This tool can retrieve some RDP information that can be use by attacker for further
  attack like Name of the user , Name of the session on the Remote Desktop Session
  Host server, Session ID, State of the session (active or disconnected), Idle time
  (the number of minutes since the last keystroke or mouse movement at the session)
  and Date and time the user logged on.
data_source:
- Sysmon EventID 1
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
  as lastTime from datamodel=Endpoint.Processes where Processes.process_name="quser.exe"
  OR Processes.original_file_name = "quser.exe" by Processes.process_name Processes.original_file_name
  Processes.process Processes.process_id Processes.process_guid Processes.parent_process_name
  Processes.parent_process Processes.parent_process_guid Processes.dest Processes.user
  | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
  | `windows_system_user_discovery_via_quser_filter`'
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: network administrator can use this command tool to audit RDP
  access of user in specific network or host.
references:
- https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/quser
- https://github.com/carlospolop/PEASS-ng/tree/master/winPEAS
- https://www.microsoft.com/en-us/security/blog/2022/10/14/new-prestige-ransomware-impacts-organizations-in-ukraine-and-poland/
tags:
  analytic_story:
  - Windows Post-Exploitation
  - Prestige Ransomware
  asset_type: Endpoint
  confidence: 30
  impact: 30
  message: execution of process $process_name$ in $dest$
  mitre_attack_id:
  - T1033
  observable:
  - name: dest
    type: Hostname
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  required_fields:
  - _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
  - Processes.parent_process_guid
  - Processes.process_guid
  risk_score: 9
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/winpeas/sysmon.log
    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
    sourcetype: xmlwineventlog
    update_timestamp: true