Microsoft Remote Desktop Protocol (RDP) Detection

# Copyright (C) 2009 Greenbone Networks GmbH
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-or-later
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.100062");
  script_version("2021-04-16T08:08:22+0000");
  script_tag(name:"last_modification", value:"2021-04-16 08:08:22 +0000 (Fri, 16 Apr 2021)");
  script_tag(name:"creation_date", value:"2009-03-19 19:54:28 +0100 (Thu, 19 Mar 2009)");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:N/I:N/A:N");
  script_tag(name:"cvss_base", value:"0.0");
  script_name("Microsoft Remote Desktop Protocol (RDP) Detection");
  script_category(ACT_GATHER_INFO);
  script_family("Service detection");
  script_copyright("Copyright (C) 2009 Greenbone Networks GmbH");
  script_dependencies("find_service.nasl", "find_service1.nasl");
  script_require_ports("Services/unknown", "Services/ms-wbt-server", 3389);

  script_tag(name:"summary", value:"A service supporting the Microsoft Remote Desktop Protocol (RDP)
  is running at this host.");

  script_tag(name:"insight", value:"Remote Desktop Services, formerly known as Terminal Services, is
  one of the components of Microsoft Windows (both server and client versions) that allows a user to
  access applications and data on a remote computer over a network.");

  script_tag(name:"qod_type", value:"remote_banner");

  exit(0);
}

include("port_service_func.inc");
include("list_array_func.inc");
include("host_details.inc");
include("os_func.inc");

SCRIPT_DESC = "Microsoft Remote Desktop Protocol (RDP) Detection";
BANNER_TYPE = "Microsoft Remote Desktop Protocol (RDP)";

function check_xrdp( port ) {

  local_var port, soc, req, buf, hexbuf;

  if( get_kb_item( "rdp/" + port + "/isxrdp" ) ) return TRUE;

  # Enforce plaintext, if we're using SSL/TLS the detection below
  # seems to fail and we only want to catch the first response anyway...
  soc = open_sock_tcp( port, transport:ENCAPS_IP );
  if( ! soc ) return FALSE;

  req = 'GET / HTTP/1.0\r\n\r\n';
  send( socket:soc, data:req );
  buf = recv( socket:soc, length:9 );
  close( soc );
  if( isnull( buf ) || strlen( buf ) != 9 ) return FALSE;

  hexbuf = hexstr( buf );

  # Some older Xrdp versions are responding with the string below
  # if a GET request is sent (see find_service1.nasl)
  if( hexbuf == "0300000902f0802180" )
    return TRUE;

  return FALSE;
}

function check_without_cookie( port ) {

  local_var port, soc, req, buf, hexbuf;

  # Enforce plaintext, if we're using SSL/TLS the detection below
  # seems to fail and we only want to catch the first response anyway...
  soc = open_sock_tcp( port, transport:ENCAPS_IP );
  if( ! soc ) return FALSE;

  # found in amap (https://github.com/BlackArch/amap/blob/master/appdefs.trig#L60)
  req = raw_string( 0x03, 0x00, 0x00, 0x0b, 0x06,
                    0xe0, 0x00, 0x00, 0x00, 0x00, 0x00 );

  send( socket:soc, data:req );
  buf = recv( socket:soc, length:11 );
  close( soc );
  if( isnull( buf ) || strlen( buf ) != 11 ) return FALSE;

  hexbuf = hexstr( buf );

  # All tested windows systems and Xrdp on Debian 9 returned the first string
  # where Xrdp on Debian 8 the latter. For the second case there is check_xrdp above.
  if( hexbuf =~ "^0300000b06d00000123400$" || hexbuf =~ "^0300000b06d00000000000$" )
    return TRUE;

  return FALSE;
}

function check_with_cookie( port ) {

  local_var port, soc, req, buf, hexbuf;

  # Enforce plaintext, if we're using SSL/TLS the detection below
  # seems to fail and we only want to catch the first response anyway...
  soc = open_sock_tcp( port, transport:ENCAPS_IP );
  if( ! soc ) return FALSE;

  # From a wireshark dump when connecting via remmina
  # to a remote RDP service running on Windows 10.
  # Also see http://www.jasonfilley.com/rdpcookies.html
  # nb: This is required if the Windows System has "Allow Connections Only From Computers Running
  # Remote Desktop With Network Level Authentication (More Secure)." enabled.
  req  = raw_string( 0x03, 0x00, 0x00 );
  req += "-("; # nb: This seems to be changed / variable depending on the cookie name below...
  req += raw_string( 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00 );
  req += 'Cookie: mstshash=openvas\r\n';
  req += raw_string( 0x01, 0x00, 0x08, 0x00, 0x03, 0x00, 0x00, 0x00 );

  send( socket:soc, data:req );
  buf = recv( socket:soc, length:19 );
  close( soc );
  if( isnull( buf ) || ( strlen( buf ) != 11 && strlen( buf ) != 19 ) ) return FALSE;

  hexbuf = hexstr( buf );

  # Those are basic fingerprints which might even change based on the RDP configuration.
  # TODO: We should evaluate more fingerprints for a reliable Detection
  if( hexbuf =~ "^030000130ed000001234000200080002000000$" )
    return make_list( "Windows, possible Windows Vista or Server 2008", hexbuf );

  if( hexbuf =~ "^030000130ed000001234000209080002000000$" || hexbuf =~ "^030000130ed000001234000201080002000000$" )
    return make_list( "Windows, possible Windows 7 or Server 2008", hexbuf );

  if( hexbuf =~ "^030000130ed00000123400021f080002000000$" )
    return make_list( "Windows, possible Windows 10 or Server 2016", hexbuf );

  if( hexbuf =~ "^030000130ed00000123400020f080002000000$" )
    return make_list( "Windows, possible Windows 8, 8.1 or Server 2012", hexbuf );

  if( hexbuf =~ "^030000130ed000001234000300080002000000$" )
    return make_list( "Windows, possible Windows XP 64bit SP2 or Server 2003", hexbuf );

  if( hexbuf =~ "^030000130ed000001234000207080002000000$" )
    return make_list( "Windows, possible Windows 8 build 9200", hexbuf );

  # Some Windows variants (e.g. Windows XP) returned this shorter string
  if( hexbuf =~ "^0300000b06d00000123400$" )
    return make_list( "Windows, possible Windows XP SP2/SP3", hexbuf );

  # Xrdp on Debian 8
  if( hexbuf =~ "^0300000b06d00000000000$" )
    return make_list( "Unixoide", hexbuf );

  # Xrdp on Debian 9
  if( hexbuf =~ "^030000130ed000001234000201080000000000$" )
    return make_list( "Unixoide", hexbuf );

  # Unknown implementation
  if( hexbuf =~ "^030000130ed000001234000....80002000000$" )
    return make_list( "Unknown", hexbuf );

  return FALSE;
}

# The default port. TBD: Add others like 3388?
ports = make_list( 3389 );

unknown_ports = unknownservice_get_ports( default_port_list:make_list( 3389 ) );
if( ! isnull( unknown_ports ) )
  ports = make_list( ports, unknown_ports );

known_ports = service_get_ports( default_port_list:make_list( 3389 ), proto:"ms-wbt-server" ); # If Xrdp was detected in find_service1.nasl...
if( ! isnull( known_ports ) )
  ports = make_list( ports, known_ports );

ports = make_list_unique( ports );

foreach port( ports ) {

  if( ! get_port_state( port ) )
    continue;

  found  = FALSE;
  isxrdp = FALSE;

  if( fp = check_with_cookie( port:port ) ) {
    found = TRUE;
  }

  if( ! found ) {
    if( check_without_cookie( port:port ) ) {
      found = TRUE;
      if( check_xrdp( port:port ) )
        isxrdp = TRUE;
    }
  }

  if( found ) {
    if( fp ) {
      report = fp[0] + " based on binary response fingerprinting: " + fp[1];
      if( "Windows" >< fp[0] ) {
        os_register_and_report( os:"Microsoft Windows", cpe:"cpe:/o:microsoft:windows", banner:report, banner_type:BANNER_TYPE, port:port, desc:SCRIPT_DESC, runs_key:"windows" );
        set_kb_item( name:"msrdp/detected", value:TRUE );
        set_kb_item( name:"rdp/detected", value:TRUE );
      } else if( "Unixoide" >< fp[0] ) {
        os_register_and_report( os:"Linux/Unix", cpe:"cpe:/o:linux:kernel", banner:report, banner_type:BANNER_TYPE, port:port, desc:SCRIPT_DESC, runs_key:"unixoide" );
        set_kb_item( name:"rdp/detected", value:TRUE );
      } else {
        os_register_unknown_banner( banner:report, banner_type_name:BANNER_TYPE, banner_type_short:"rdp_binary_response", port:port );
        set_kb_item( name:"msrdp/detected", value:TRUE );
        set_kb_item( name:"rdp/detected", value:TRUE );
      }
    } else {
      if( isxrdp ) {
        os_register_and_report( os:"Linux/Unix", cpe:"cpe:/o:linux:kernel", banner:"Connection reset message of Xrdp", banner_type:BANNER_TYPE, port:port, desc:SCRIPT_DESC, runs_key:"unixoide" );
        set_kb_item( name:"rdp/detected", value:TRUE );
      } else {
        set_kb_item( name:"msrdp/detected", value:TRUE );
        set_kb_item( name:"rdp/detected", value:TRUE );
      }
    }
    service_register( port:port, proto:"ms-wbt-server" );
    log_message( port:port );
  }
}

exit( 0 );