SSL/TLS: FTP 'AUTH TLS' Command Detection

# SPDX-FileCopyrightText: 2014 Greenbone AG
# 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-only

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.105009");
  script_version("2023-07-26T05:05:09+0000");
  script_tag(name:"last_modification", value:"2023-07-26 05:05:09 +0000 (Wed, 26 Jul 2023)");
  script_tag(name:"creation_date", value:"2014-04-09 16:39:22 +0100 (Wed, 09 Apr 2014)");
  script_tag(name:"cvss_base", value:"0.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:N/I:N/A:N");
  script_name("SSL/TLS: FTP 'AUTH TLS' Command Detection");
  script_category(ACT_GATHER_INFO);
  script_family("SSL and TLS");
  script_copyright("Copyright (C) 2014 Greenbone AG");
  script_dependencies("ftpserver_detect_type_nd_version.nasl");
  script_require_ports("Services/ftp", 21);
  script_mandatory_keys("ftp/banner/available");

  script_tag(name:"summary", value:"Checks if the remote FTP server supports SSL/TLS (FTPS) with the 'AUTH TLS' command.");

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

  script_xref(name:"URL", value:"https://tools.ietf.org/html/rfc4217");

  exit(0);
}

include("ftp_func.inc");
include("misc_func.inc");
include("port_service_func.inc");

port = ftp_get_port( default:21 );

if( get_port_transport( port ) > ENCAPS_IP )
  exit( 0 );

soc = open_sock_tcp( port );
if( ! soc )
  exit( 0 );

buf = ftp_recv_line( socket:soc );
if( ! buf ) {
  ftp_close( socket:soc );
  exit( 0 );
}

buf = ftp_send_cmd( socket:soc, cmd:'AUTH TLS\r\n' );
ftp_close( socket:soc );
if( ! buf )
  exit( 0 );

if( "234" >< buf ) {
  set_kb_item( name:"ftp/starttls/supported", value:TRUE );
  set_kb_item( name:"ftp/" + port + "/starttls", value:TRUE );
  set_kb_item( name:"starttls_typ/" + port, value:"ftp" );
  log_message( port:port, data:"The remote FTP server supports TLS (FTPS) with the 'AUTH TLS' command." );
} else {
  set_kb_item( name:"ftp/starttls/not_supported", value:TRUE );
  set_kb_item( name:"ftp/starttls/not_supported/port", value:port );
}

exit( 0 );