Microsoft Windows: Microsoft network server: Server SPN target name validation level

##############################################################################
# OpenVAS Vulnerability Test
# $Id: win_ns_spn_validation_level.nasl 11532 2018-09-21 19:07:30Z cfischer $
#
# Check value for Microsoft network server: Server SPN target name validation level
#
# Authors:
# Emanuel Moss <[email protected]>
#
# Copyright:
# Copyright (c) 2018 Greenbone Networks GmbH, http://www.greenbone.net
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2
# (or any later version), as published by the Free Software Foundation.
#
# 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.
###############################################################################

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.109216");
  script_version("$Revision: 11532 $");
  script_tag(name:"last_modification", value:"$Date: 2018-09-21 21:07:30 +0200 (Fri, 21 Sep 2018) $");
  script_tag(name:"creation_date", value:"2018-06-08 16:04:47 +0200 (Fri, 08 Jun 2018)");
  script_tag(name:"cvss_base", value:"0.0");
  script_tag(name:"cvss_base_vector", value:"AV:L/AC:H/Au:S/C:N/I:N/A:N");
  script_tag(name:"qod", value:"97");
  script_name('Microsoft Windows: Microsoft network server: Server SPN target name validation level');
  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (c) 2018 Greenbone Networks GmbH");
  script_family("Policy");
  script_dependencies("smb_reg_service_pack.nasl");
  script_add_preference(name:"Value", type:"radio", value:"1;0");
  script_mandatory_keys("Compliance/Launch");
  script_tag(name:"summary", value:"This test checks the setting for policy
'Microsoft network server: Server SPN target name validation level' on Windows
hosts (at least Windows 7).

The policy setting controls the level of validation that a server with shared
folders or printers performs on the service principal name (SPN) that is
provided by the client device when the client device establishes a session by
using the Server Message Block (SMB) protocol. The level of validation can help
prevent a class of attacks against SMB services.
This setting affects both SMB1 and SMB2.");
  exit(0);
}

include("smb_nt.inc");
include("policy_functions.inc");

if(!get_kb_item("SMB/WindowsVersion")){
  policy_logging(text:'Host is no Microsoft Windows System or it is not possible
to query the registry.');
  exit(0);
}

if(get_kb_item("SMB/WindowsVersion") < "6.1"){
  policy_logging(text:'Host is not at least a Microsoft Windows 7 system.
Older versions of Windows are not supported any more. Please update the
Operating System.');
  exit(0);
}

title = 'Microsoft network server: Server SPN target name validation level';
fixtext = 'Set following UI path accordingly:
Computer Configuration/Windows Settings/Security Settings/Local Policies/Security Options/' + title;
type = 'HKLM';
key = 'SYSTEM\\CurrentControlSet\\Services\\LanManServer\\Parameters';
item = 'SMBServerNameHardeningLevel';
default = script_get_preference('Value');
value = registry_get_dword(key:key, item:item, type:type);

if( value == ''){
  value = '0';
}

if(int(value) == int(default)){
  compliant = 'yes';
}else{
  compliant = 'no';
}

policy_logging(text:'"' + title + '" is set to: ' + value);
policy_add_oid();
policy_set_dval(dval:default);
policy_fixtext(fixtext:fixtext);
policy_control_name(title:title);
policy_set_kb(val:value);
policy_set_compliance(compliant:compliant);

exit(0);