name: Linux Ngrok Reverse Proxy Usage
id: bc84d574-708c-467d-b78a-4c1e20171f97
version: 1
date: '2023-01-12'
author: Michael Haag, Splunk
type: Anomaly
datamodel:
- Endpoint
description: The following analytic identifies the use of Ngrok being utilized on the Linux operating system. Unfortunately, there is no original file name for Ngrok, so it may be worth an additional hunt to identify any command-line arguments.
  The sign of someone using Ngrok is not malicious, however, more recently it has become an adversary tool.
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:  To successfully implement this search, you need to be ingesting
  logs with the process name, parent process, and command-line executions from your
  endpoints into the Endpoint datamodel. If you are using Sysmon, you can use the Add-on for Linux Sysmon from
  Splunkbase.
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
  cis20:
  - CIS 3
  - CIS 5
  - CIS 16
  confidence: 100
  context:
  - Source:Endpoint
  - Stage:Defense Evasion
  dataset:
  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1572/ngrok/ngrok_linux-sysmon.log
  impact: 50
  kill_chain_phases:
  - Command & Control
  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
  nist:
  - DE.CM
  observable:
  - name: user
    type: User
    role:
    - Victim
  - name: dest
    type: Hostname
    role:
    - Victim
  - name: parent_process_name
    type: Process
    role:
    - Parent Process
  - name: process_name
    type: Process
    role:
    - Child Process
  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