Avirt gateway insecure telnet proxy

# SPDX-FileCopyrightText: 2002 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

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.11096");
  script_version("2023-08-01T13:29:10+0000");
  script_tag(name:"last_modification", value:"2023-08-01 13:29:10 +0000 (Tue, 01 Aug 2023)");
  script_tag(name:"creation_date", value:"2005-11-03 14:08:04 +0100 (Thu, 03 Nov 2005)");
  script_xref(name:"URL", value:"http://www.securityfocus.com/bid/3901");
  script_tag(name:"cvss_base", value:"7.5");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_cve_id("CVE-2002-0134");
  script_name("Avirt gateway insecure telnet proxy");
  script_category(ACT_ATTACK);
  script_tag(name:"qod_type", value:"remote_banner");
  script_copyright("Copyright (C) 2002 Michel Arboi");
  script_family("Gain a shell remotely");
  script_dependencies("telnetserver_detect_type_nd_version.nasl");
  script_require_ports("Services/telnet", 23);
  script_mandatory_keys("telnet/banner/available");

  script_tag(name:"solution", value:"Contact your vendor for a patch or disable this service.");

  script_tag(name:"summary", value:"It was possible to connect to the remote telnet server without
  password and to get a command prompt with the 'DOS' command.");

  script_tag(name:"impact", value:"An attacker may use this flaw to get access on your system.");

  script_tag(name:"solution_type", value:"Mitigation");

  exit(0);
}

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

port = telnet_get_port(default:23);

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

banner = telnet_negotiate(socket:soc);
cmd = string("dos\r\n");
send(socket:soc, data:cmd);
res = recv(socket:soc, length:512);

close(soc);
flag = egrep(pattern:"^[A-Z]:\\.*>", string:res);
if(flag) {
  security_message(port:port);
  exit(0);
}

exit(99);