Microsoft Windows: Configure minimum PIN length for startup

##############################################################################
# OpenVAS Vulnerability Test
# $Id: win_min_pin_len_startup.nasl 11363 2018-09-12 13:46:05Z emoss $
#
# Check value for Configure minimum PIN length for startup
#
# 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("1.3.6.1.4.1.25623.1.0.109397");
  script_version("$Revision: 11363 $");
  script_tag(name:"last_modification", value:"$Date: 2018-09-12 15:46:05 +0200 (Wed, 12 Sep 2018) $");
  script_tag(name:"creation_date", value:"2018-06-26 09:23:34 +0200 (Tue, 26 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: Configure minimum PIN length for startup');
  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:"Minimum", type:"entry", value:"7");
  script_mandatory_keys("Compliance/Launch");
  script_tag(name:"summary", value:"This test checks the setting for policy
'Configure minimum PIN length for startup' on Windows hosts (at least Windows 7).

The setting configures a minimum length for a Trusted Platform Module (TPM)
startup PIN. The setting is applied when you turn on BitLocker.
The startup PIN must have a minimum length of 4 digits and can have a maximum
length of 20 digits.");
  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 Microsoft Windows are not supported any more.
Please update the system.');
  exit(0);
}

title = 'Configure minimum PIN length for startup';
fixtext = 'Set following UI path accordingly:
Computer Configuration/Administrative Templates/Windows Components/
BitLocker Drive Encryption/Operating System Drives/' + title;
type = 'HKLM';
key = 'Software\\Policies\\Microsoft\\FVE';
item = 'MinimumPIN';
value = registry_get_dword(key:key, item:item, type:type);
default = script_get_preference('Minimum');

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);