cis_security_hardening_windows

Table of Contents

1. Overview
2. Description
3. Building on CIS controls
   • Windows 10 / 11
   • Defence in-depth
4. Beginning with os_hardening
5. CIS Enforcement Levels
6. Reference
7. Development
8. Release Notes

Overview

This module applies CIS benchmark hardening with a default 100% validation pass and 100% test coverage to:

• Windows 10: Configurable, defaulted to domain-joined Level 1 & 2 + NG + BL (currently v3.0.0)
• Windows 11: Configurable, defaulted to domain-joined Level 1 & 2 + BL (currently v3.0.0)

It also configures additional system resources as described below

Description

Windows CIS controls and other resources are applied using registry, security policy, audit policy, optional local group policy (for HKCU controls), execs and dependency modules.

This module uses a custom windows facts hash leveraging wmi, as reading the registry is unreliable for Windows 11 (and predicted for future versions).

Building on CIS controls

Additional resources are also defined, including:

Windows 10 / 11

• users
• remote desktop
• firewall (limited)

Other Windows 10 / 11 parameters include:

• cis_profile_type
• cis_enforcement_level
• cis_include_bitlocker
• cis_include_nextgen
• cis_include_hkcu
• cis_exclude_rules
• catalog_no_cache
• clear_temp_files
• enable_administrator
• purge_unmanaged_users
• performance_powerscheme
• enable_remote_desktop

Defence in-depth

This module takes a defence in-depth approach, with the following built-in functions:

• undefined users can be optionally purged (except system users)
• where CIS recommendations have more than 1 acceptable setting, the more stringent is used

Beginning with cis_security_hardening_windows

To use this module, include cis_security_hardening_windows in your Node Classifier (ENC) or wrapping class.

At minimum, the following hiera must be provided to the module:

Windows 10 / 11:

• cis_security_hardening_windows::logon_banner (string)
• cis_security_hardening_windows::logon_message (string)
• cis_security_hardening_windows::administrator_newname (string)
• cis_security_hardening_windows::administrator_newpassword (string)
• cis_security_hardening_windows::disabled_guest_newname (string)
• cis_security_hardening_windows::users (hash) is required if the built-in administrator is disabled (default)

See example minimum hiera data here

CIS Enforcement Levels

• All recommended domain-joined Level 1 & 2 + NG + BL CIS controls are enforced by default using module hiera (standalone selectable)
• HKCU registry entries are also optionally applied by copying a preconfigured Registry.pol file to C:/Windows/System32/GroupPolicy/
• Comments in module hiera identify the objective of each setting however CIS reference numbers are not shown as they are subject to change
• Profile Type, Enforcement Level (1 or 2 (1+2)), BitLocker (BL), NextGen (NG) and HKCU policy inclusion are parameterised:

  cis_security_hardening_windows::cis_profile_type:      'domain'
  cis_security_hardening_windows::cis_enforcement_level: 2
  cis_security_hardening_windows::cis_include_bitlocker: true
  cis_security_hardening_windows::cis_include_nextgen:   true
  cis_security_hardening_windows::cis_include_hkcu:      true

• A reference list of rules enforced via the system registry is in the hiera folder for each Windows version, eg here. Note that some additional rules are applied by Local Security Policy and Audit Policy resources however.
• Individual controls can be overridden by any of the following methods:
  • creating a optional hiera array for cis_security_hardening_windows::cis_exclude_rules containing rule titles to be subtracted from the default included hashes (note that some rules are managed by the local_security_policy or cis_auditpol):

    cis_security_hardening_windows::cis_exclude_rules:
      - "(L1) Ensure 'Allow users to enable online speech recognition services is set to 'Disabled'"
      - "(L1) Ensure 'Configure Solicited Remote Assistance' is set to 'Disabled'"

  • creating a hiera hash containing keys with different values at a higher precedence (eg domain or node) and titled any of:

    cis_security_hardening_windows::cis_level_1
    cis_security_hardening_windows::cis_level_2
    cis_security_hardening_windows::cis_bitlocker
    cis_security_hardening_windows::cis_nextgen
    cis_security_hardening_windows::cis_secpol_level_1
    cis_security_hardening_windows::cis_secpol_level_2
    cis_security_hardening_windows::cis_auditpol

  • other methods such as resource collectors to override registry key values if wrapping this module into your own class or control repo

Reference

See the Puppet Strings documentation.

Development

Github repo is available for contributions at https://github.com/canihavethisone/cis_security_hardening_windows

Release Notes

See changelog