splunk-security_content/detections/endpoint/linux_ngrok_reverse_proxy_usage.yml

name: Linux Ngrok Reverse Proxy Usage
id: bc84d574-708c-467d-b78a-4c1e20171f97
version: 3
date: '2024-08-14'
author: Michael Haag, Splunk
status: production
type: Anomaly
description: The following analytic detects the use of Ngrok on a Linux operating
  system. It leverages data from Endpoint Detection and Response (EDR) agents, focusing
  on process names and command-line arguments associated with Ngrok. This activity
  is significant because Ngrok can be used by adversaries to establish reverse proxies,
  potentially bypassing network defenses. If confirmed malicious, this could allow
  attackers to create persistent, unauthorized access channels, facilitating data
  exfiltration or further exploitation of the compromised system.
data_source:
- Sysmon for Linux EventID 1
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
  as lastTime from datamodel=Endpoint.Processes where Processes.process_name=ngrok
  Processes.process IN ("*start*", "*--config*","*http*","*authtoken*", "*http*",
  "*tcp*") by Processes.dest Processes.user Processes.parent_process_name Processes.process_name
  Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id
  | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
  | `linux_ngrok_reverse_proxy_usage_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: False positives may be present if Ngrok is an authorized utility.
  Filter as needed.
references:
- https://ngrok.com
- https://www.cisa.gov/uscert/sites/default/files/publications/aa22-320a_joint_csa_iranian_government-sponsored_apt_actors_compromise_federal%20network_deploy_crypto%20miner_credential_harvester.pdf
tags:
  analytic_story:
  - Reverse Network Proxy
  asset_type: Endpoint
  confidence: 100
  impact: 50
  message: A reverse proxy was identified spawning from $parent_process_name$ -  $process_name$
    on endpoint $dest$ by user $user$.
  mitre_attack_id:
  - T1572
  - T1090
  - T1102
  observable:
  - name: user
    type: User
    role:
    - Victim
  - name: dest
    type: Hostname
    role:
    - Victim
  - name: parent_process_name
    type: Process
    role:
    - Attacker
  - name: process_name
    type: Process
    role:
    - Attacker
  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
  risk_score: 50
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: 
      https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1572/ngrok/ngrok_linux-sysmon.log
    source: Syslog:Linux-Sysmon/Operational
    sourcetype: sysmon:linux
    update_timestamp: true