Grandstream Devices Backdoor Credentials (Telnet)

# SPDX-FileCopyrightText: 2013 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("1.3.6.1.4.1.25623.1.0.103737");
  script_version("2023-07-27T05:05:08+0000");
  script_cve_id("CVE-2013-3542", "CVE-2013-3962", "CVE-2013-3963");
  script_tag(name:"cvss_base", value:"10.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:C/I:C/A:C");

  script_name("Grandstream Devices Backdoor Credentials (Telnet)");

  script_xref(name:"URL", value:"http://seclists.org/fulldisclosure/2013/Jun/84");

  script_tag(name:"last_modification", value:"2023-07-27 05:05:08 +0000 (Thu, 27 Jul 2023)");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2019-12-19 20:21:00 +0000 (Thu, 19 Dec 2019)");
  script_tag(name:"creation_date", value:"2013-06-11 14:29:08 +0200 (Tue, 11 Jun 2013)");
  script_category(ACT_ATTACK);
  script_tag(name:"qod_type", value:"remote_vul");
  script_family("Default Accounts");
  script_copyright("Copyright (C) 2013 Greenbone AG");
  script_dependencies("telnetserver_detect_type_nd_version.nasl", "gb_default_credentials_options.nasl");
  script_require_ports("Services/telnet", 23);
  script_exclude_keys("default_credentials/disable_default_account_checks");

  script_tag(name:"solution", value:"No known solution was made available for at least one year since the
  disclosure of this vulnerability. Likely none will be provided anymore. General solution options are to
  upgrade to a newer release, disable respective features, remove the product or replace the product by
  another one.");

  script_tag(name:"solution_type", value:"WillNotFix");
  script_tag(name:"summary", value:"The remote Grandstream device has the default telnet user and password '!#/'.");
  exit(0);
}

if(get_kb_item("default_credentials/disable_default_account_checks"))
  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);

buf = recv(socket:soc, length:512);

if("grandstream" >!< buf || "Username" >!< buf)
  exit(0);

up = '!#/';

send(socket:soc, data:up + '\r\n');
ret = recv(socket:soc, length:512);

if("Password" >!< ret)
  exit(0);

send(socket:soc, data:up + '\r\n');
ret = recv(socket:soc, length:512);

close(soc);

if("Grandstream>" >< ret) {
  security_message(port:port);
  exit(0);
}

exit(0);