Microsoft Windows: BitLocker-protected removable drives recovery (key)

##############################################################################
# OpenVAS Vulnerability Test
# $Id: win_rm_bitlocker_recovery_key.nasl 11363 2018-09-12 13:46:05Z emoss $
#
# Check value for Choose how BitLocker-protected removable drives can be
# recovered: Recovery Key
#
# 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("1.3.6.1.4.1.25623.1.0.109413");
  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 11:45:30 +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: BitLocker-protected removable drives recovery (key)');
  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:"0;1;2");
  script_mandatory_keys("Compliance/Launch");
  script_tag(name:"summary", value:"This test checks the setting for policy
'Choose how BitLocker-protected removable drives can be recovered: Recovery
Key' on Windows hosts (at least Windows 7).

The setting controls how BitLocker-protected removable data drives are recovered
in the absence of the required credentials.
This policy setting is applied when you turn on BitLocker.
The option specifies whether users are allowed, required, or not allowed to
generate a 256-bit recovery key.");
  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 = 'Choose how BitLocker-protected removable drives can be recovered:
Recovery Key';
fixtext = 'Set following UI path accordingly:
Computer Configuration/Administrative Templates/Windows Components/
BitLocker Drive Encryption/Removable Data Drives/' + title;
type = 'HKLM';
key = 'Software\\Policies\\Microsoft\\FVE';
item = 'RDVRecoveryKey';
value = registry_get_dword(key:key, item:item, type:type);
default = script_get_preference('Value');

if(value == ''){
  value = '2';
}

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);