Cisco Nexus 9000 Series Switches Telnet Login Denial of Service Vulnerability (cisco-sa-20170315-nss)

# Copyright (C) 2017 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.

CPE = "cpe:/o:cisco:nx-os";

if (description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.106657");
  script_version("2022-12-26T10:12:01+0000");
  script_tag(name:"last_modification", value:"2022-12-26 10:12:01 +0000 (Mon, 26 Dec 2022)");
  script_tag(name:"creation_date", value:"2017-03-16 11:30:46 +0700 (Thu, 16 Mar 2017)");
  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_tag(name:"severity_vector", value:"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2017-07-12 01:29:00 +0000 (Wed, 12 Jul 2017)");

  script_cve_id("CVE-2017-3878");

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

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

  script_name("Cisco Nexus 9000 Series Switches Telnet Login Denial of Service Vulnerability (cisco-sa-20170315-nss)");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2017 Greenbone Networks GmbH");
  script_family("CISCO");
  script_dependencies("gb_cisco_nx_os_consolidation.nasl");
  script_mandatory_keys("cisco/nx_os/detected", "cisco/nx_os/device", "cisco/nx_os/model");

  script_tag(name:"summary", value:"A vulnerability in the Telnet remote login functionality of
  Cisco NX-OS Software running on Cisco Nexus 9000 Series Switches could allow an unauthenticated,
  remote attacker to cause a Telnet process used for login to terminate unexpectedly and the login
  attempt to fail. There is no impact to user traffic flowing through the device.");

  script_tag(name:"vuldetect", value:"Checks if a vulnerable version is present on the target host.");

  script_tag(name:"insight", value:"The vulnerability is due to incomplete input validation of
  Telnet packet headers. An attacker could exploit this vulnerability by sending a crafted Telnet
  packet to an affected system during a remote Telnet login attempt.");

  script_tag(name:"impact", value:"A successful exploit could allow the attacker to cause the
  Telnet process on the affected system to restart unexpectedly, resulting in a denial of service
  (DoS) condition for the Telnet process.");

  script_tag(name:"solution", value:"See the referenced vendor advisory for a solution.");

  script_xref(name:"URL", value:"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170315-nss");

  exit(0);
}

include("host_details.inc");
include("version_func.inc");

if (!device = get_kb_item("cisco/nx_os/device"))
  exit(0);

if ("Nexus" >!< device)
  exit(0);

if (!nx_model = get_kb_item("cisco/nx_os/model"))
  exit(0);

if (nx_model !~ "^C?[0-9]{3}")
  exit(0);

if (!version = get_app_version(cpe: CPE, nofork: TRUE))
  exit(0);

if (version == "7.0(3)I3(0.170)") {
  report = report_fixed_ver(installed_version: version, fixed_version: "See advisory");
  security_message(port: 0, data: report);
  exit(0);
}

exit(99);