awesome-security-hardening

A collection of awesome security hardening guides, best practices, checklists, benchmarks, tools and other resources. This is work in progress: please contribute by sending your suggestions. You may do this by creating issue tickets or forking, editing and sending pull requests. You may also send suggestions on Twitter to @decalage2, or use https://www.decalage.info/contact

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Table of Contents

• Security Hardening Guides and Best Practices
  • Hardening Guide Collections
  • GNU/Linux
    • Red Hat Enterprise Linux - RHEL
    • CentOS
    • SUSE
    • Ubuntu
  • Windows
  • macOS
  • Network Devices
    • Switches
    • Routers
    • IPv6
    • Firewalls
  • Virtualization - VMware
  • Containers - Docker - Kubernetes
  • Services
    • SSH
    • TLS/SSL
    • Web Servers
      • Apache HTTP Server
      • Apache Tomcat
      • Eclipse Jetty
      • Microsoft IIS
    • Mail Servers
    • FTP Servers
    • Database Servers
    • Active Directory
    • ADFS
    • Kerberos
    • LDAP
    • DNS
    • NTP
    • NFS
    • CUPS
  • Authentication - Passwords
  • Hardware - CPU - BIOS - UEFI
  • Cloud
• Tools
  • Tools to check security hardening
    • GNU/Linux
    • Windows
    • Network Devices
    • TLS/SSL
    • SSH
    • Hardware - CPU - BIOS - UEFI
    • Docker
    • Cloud
    • DNS
  • Tools to apply security hardening
    • GNU/Linux
    • Windows
    • TLS/SSL
    • Cloud
  • Password Generators
• Books
• Other Awesome Lists
  • Other Awesome Security Lists

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Security Hardening Guides and Best Practices

Hardening Guide Collections

• CIS Benchmarks (registration required)
• ANSSI Guides
• NSA Cybersecurity Advisories & Guidance
• NSA Cybersecurity Resources for Cybersecurity Professionals and NSA Cybersecurity publications
• US DoD DISA Security Technical Implementation Guides (STIGs) and Security Requirements Guides (SRGs)
• OpenSCAP Security Policies
• Australian Cyber Security Center Publications
• FIRST Best Practice Guide Library (BPGL)
• Harden the World - a collection of hardening guidelines for devices, applications and OSs (mostly Apple for now).

GNU/Linux

• ANSSI - Configuration recommendations of a GNU/Linux system - version 2.0, 2022
• CIS Benchmark for Distribution Independent Linux - 2019, archived
• trimstray - The Practical Linux Hardening Guide - practical step-by-step instructions for building your own hardened systems and services. Tested on CentOS 7 and RHEL 7.
• trimstray - Linux Hardening Checklist - most important hardening rules for GNU/Linux systems (summarized version of The Practical Linux Hardening Guide)
• How To Secure A Linux Server - for a single Linux server at home
• nixCraft - 40 Linux Server Hardening Security Tips (2019 edition)
• nixCraft - Tips To Protect Linux Servers Physical Console Access
• TecMint - 4 Ways to Disable Root Account in Linux
• ERNW - IPv6 Hardening Guide for Linux Servers
• trimstray - Iptables Essentials: Common Firewall Rules and Commands
• Neo23x0/auditd - Best Practice Auditd Configuration
• CIRCL TR-83 - Linux Boot Hardening HOWTO - How to secure the boot sequence of your Linux based distribution (2024)

Red Hat Enterprise Linux - RHEL

• Red Hat - A Guide to Securing Red Hat Enterprise Linux 7
• DISA STIGs - Red Hat Enterprise Linux 7 (2019)
• CIS Benchmark for Red Hat Linux
• nixCraft - How to set up a firewall using FirewallD on RHEL 8

CentOS

• Lisenet - CentOS 7 Server Hardening Guide (2017)
• HighOn.Coffee - Security Harden CentOS 7 (2015)

SUSE

• SUSE Linux Enterprise Server 12 SP4 Security Guide
• SUSE Linux Enterprise Server 12 Security and Hardening Guide

Ubuntu

• Ubuntu documentation - Security
• Ubuntu wiki - Security Hardening Features

Windows

• Microsoft - Windows security baselines
• Microsoft - Windows Server Security | Assurance
• Microsoft - Windows 10 Enterprise Security
• BSI/ERNW - Configuration Recommendations for Hardening of Windows 10 Using Built-in Functionalities (2021) - focused on Windows 10 LTSC 2019
• ACSC - Hardening Microsoft Windows 10, version 21H1, Workstations
• ACSC - Securing PowerShell in the Enterprise
• Awesome Windows Domain Hardening
• Microsoft - How to detect, enable and disable SMBv1, SMBv2, and SMBv3 in Windows and Windows Server
• Microsoft recommended block rules - List of applications or files that can be used by an attacker to circumvent application whitelisting policies
• ERNW - IPv6 Hardening Guide for Windows Servers
• NSA - AppLocker Guidance - Configuration guidance for implementing application whitelisting with AppLocker
• NSA - Pass the Hash Guidance - Configuration guidance for implementing Pass-the-Hash mitigations (Archived)
• NSA - BitLocker Guidance - Configuration guidance for implementing disk encryption with BitLocker
• NSA - Event Forwarding Guidance - Configuration guidance for implementing collection of security relevant Windows Event Log events by using Windows Event Forwarding

See also Active Directory and ADFS below.

macOS

• ERNW - IPv6 Hardening Guide for OS-X

Network Devices

• NSA - Harden Network Devices (PDF) - very short but good summary

Switches

• DISA - Layer 2 Switch SRG v2r1

Routers

• NSA - A Guide to Border Gateway Protocol (BGP) Best Practices

IPv6

• NSA - IPv6 Security Guidance (Jan 2023)
• ERNW - Developing an Enterprise IPv6 Security Strategy Part 1, Part 2, Part 3, Part 4 - Network Isolation on the Routing Layer, Traffic Filtering in IPv6 Networks
• see also IPv6 links under GNU/Linux, Windows and macOS

Firewalls

• NIST SP 800-41 Rev 1 - Guidelines on Firewalls and Firewall Policy (2009)
• trimstray - Iptables Essentials: Common Firewall Rules and Commands

Virtualization - VMware

• VMware Security Hardening Guides - covers most VMware products and versions
• CIS VMware ESXi 6.5 Benchmark (2018)
• DISA STIGs - Virtualisation - VMware vSphere 6.0 and 5
• ENISA - Security aspects of virtualization - generic, high-level best practices for virtualization and containers (Feb 2017)
• NIST SP 800-125 - Guide to Security for Full Virtualization Technologies - (2011)
• NIST SP 800-125A Revision 1 - Security Recommendations for Server-based Hypervisor Platforms (2018)
• NIST SP 800-125B Secure Virtual Network Configuration for Virtual Machine (VM) Protection (2016)
• ANSSI - Recommandations de sécurité pour les architectures basées sur VMware vSphere ESXi - for VMware 5.5 (2016), in French
• ANSSI - Securing a VMware infrastructure (2026)
• VMware - Protecting vSphere From Specialized Malware (2022) - see also Mandiant - Bad VIB(E)s Part Two: Detection and Hardening within ESXi Hypervisors

Containers - Docker - Kubernetes

• How To Harden Your Docker Containers
• CIS Docker Benchmarks - registration required
• NIST SP 800-190 - Application Container Security Guide
• A Practical Introduction to Container Security
• ANSSI - Recommandations de sécurité relatives au déploiement de conteneurs Docker (2020), in French
• Kubernetes Security Checklist
• Kubernetes Role Based Access Control Good Practices
• Kubernetes Multi-tenancy
• Kubernetes blog - A Closer Look at NSA/CISA Kubernetes Hardening Guidance
• ReynardSec - Docker Security – Step-by-Step Hardening (Docker Hardening) (2023)

Services

SSH

• NIST IR 7966 - Security of Interactive and Automated Access Management Using Secure Shell (SSH)
• ANSSI - (Open)SSH secure use recommendations
• Linux Audit - OpenSSH security and hardening
• Positron Security SSH Hardening Guides (2017-2018) - focused on crypto algorithms
• stribika - Secure Secure Shell (2015) - some algorithm recommendations might be slightly outdated
• Applied Crypto Hardening: bettercrypto.org - handy reference on how to configure the most common services’ crypto settings (TLS/SSL, PGP, SSH and other cryptographic tools)
• IETF - Key Exchange (KEX) Method Updates and Recommendations for Secure Shell (SSH) draft-ietf-curdle-ssh-kex-sha2-10 - update to the recommended set of key exchange methods for use in the Secure Shell (SSH) protocol to meet evolving needs for stronger security. This document updates RFC 4250.
• Gravitational - How to SSH Properly - how to configure SSH to use certificates and two-factor authentication

TLS/SSL

• NIST SP800-52 Rev 2 (2nd draft) - Guidelines for the Selection, Configuration, and Use of Transport Layer Security (TLS) Implementations - 2018, recommends TLS 1.3
• Netherlands NCSC - IT Security Guidelines for Transport Layer Security (TLS) - 2021
• ANSSI - Security Recommendations for TLS - 2017, does not cover TLS 1.3
• Qualys SSL Labs - SSL and TLS Deployment Best Practices - 2017, does not cover TLS 1.3
• RFC 7540 Appendix A TLS 1.2 Cipher Suite Black List
• Applied Crypto Hardening: bettercrypto.org - handy reference on how to configure the most common services’ crypto settings (TLS/SSL, PGP, SSH and other cryptographic tools)

Web Servers

• Cipherlist.eu - Strong Ciphers for Apache, nginx and Lighttpd

Apache HTTP Server

• Apache HTTP Server documentation - Security Tips
• GeekFlare - Apache Web Server Hardening and Security Guide
• Apache Config - Apache Security Hardening Guide

Apache Tomcat

• Apache Tomcat 9 Security Considerations / v8 / v7
• OWASP Securing tomcat
• How to get Tomcat 9 to work with authbind to bind to port 80

Eclipse Jetty

• Eclipse Jetty - Configuring Security
• Jetty hardening (2015)

Microsoft IIS

• CIS Microsoft IIS Benchmarks

Mail Servers

• MDaemon - 15 Best Practices for Protecting Your Email - Generic recommandations but based on MDaemon Security Gateway for Email Servers

FTP Servers

• JSCAPE - Guide for securing FTP - Generic recommandations but based on JSCAPE MFT Server

Database Servers

• Netwrix - MS SQL Server Hardening Best Practices

Active Directory

• Microsoft - Best Practices for Securing Active Directory
• ANSSI CERT-FR - Active Directory Security Assessment Checklist - other version with changelog - 2022 (English and French versions)
• "Admin Free" Active Directory and Windows, Part 1- Understanding Privileged Groups in AD
• "Admin Free" Active Directory and Windows, Part 2- Protected Accounts and Groups in Active Directory
• ASD - Detecting and mitigating Active Directory compromises - 2024

ADFS

• adsecurity.org - Securing Microsoft Active Directory Federation Server (ADFS)
• Microsoft - Best practices for securing Active Directory Federation Services

Kerberos

• CIS MIT Kerberos 1.10 Benchmark - 2012

LDAP

• OpenLDAP Software 2.4 Administrator's Guide - OpenLDAP Security Considerations
• Best Practices in LDAP Security (2011)
• LDAP: Hardening Server Security (so administrators can sleep at night)
• LDAP Authentication Best Practices - retrieved from web.archive.org
• Hardening OpenLDAP on Linux with AppArmor and systemd - slides
• zytrax LDAP for Rocket Scientists - LDAP Security
• How To Encrypt OpenLDAP Connections Using STARTTLS

DNS

• CIS - BIND DNS Server 9.9 Benchmark (2017)
• DISA STIGs - BIND 9.x (2019)
• NIST SP 800-81-2 - Secure Domain Name System (DNS) Deployment Guide (2013)
• CMU SEI - Six Best Practices for Securing a Robust Domain Name System (DNS) Infrastructure
• NSA BIND 9 DNS Security (2011)

NTP

• IETF - Network Time Protocol Best Current Practices draft-ietf-ntp-bcp (last draft #13 in March 2019)
• CMU SEI - Best Practices for NTP Services
• Linux.com - Arrive On Time With NTP -- Part 2: Security Options
• Linux.com - Arrive On Time With NTP -- Part 3: Secure Setup

NFS

• Linux NFS-HOWTO - Security and NFS - a good overview of NFS security issues and some mitigations
• Red Hat - A Guide to Securing Red Hat Enterprise Linux 7 - Securing NFS
• Red Hat - RHEL7 Storage Administration Guide - Securing NFS
• NFSv4 without Kerberos and permissions - why NFSv4 without Kerberos does not provide security
• CertDepot - RHEL7: Use Kerberos to control access to NFS network shares

CUPS

• CUPS Server Security

Authentication - Passwords

• UK NCSC - Password administration for system owners
• NIST SP 800-63 Digital Identity Guidelines
• OWASP Password Storage Cheat Sheet
• ANSSI - Recommendations on multi-factor authentication and passwords (2021, French)

Hardware - CPU - BIOS - UEFI

• ANSSI - Hardware security requirements for x86 platforms - recommendations for security features and configuration options applying to hardware devices (CPU, BIOS, UEFI, etc) (Nov 2019)
• NSA - Hardware and Firmware Security Guidance - Guidance for the Spectre, Meltdown, Speculative Store Bypass, Rogue System Register Read, Lazy FP State Restore, Bounds Check Bypass Store, TLBleed, and L1TF/Foreshadow vulnerabilities as well as general hardware and firmware security guidance.
• NSA Info Sheet: UEFI Lockdown Quick Guidance (March 2018)
• NSA Tech Report: UEFI Defensive Practices Guidance (July 2017)

Cloud

• NSA Info Sheet: Cloud Security Basics (August 2018)
• DISA DoD Cloud Computing Security
• asecure.cloud - Build a Secure Cloud - A free repository of customizable AWS security configurations and best practices

Tools

Tools to check security hardening

• Chef InSpec - open-source testing framework by Chef that enables you to specify compliance, security, and other policy requirements. can run on Windows and many Linux distributions.

GNU/Linux

• Lynis - script to check the configuration of Linux hosts
• OpenSCAP Base - oscap command line tool
• SCAP Workbench - GUI for oscap
• Tiger - The Unix security audit and intrusion detection tool (might be outdated)
• otseca - Open source security auditing tool to search and dump system configuration. It allows you to generate reports in HTML or RAW-HTML formats.
• SUDO_KILLER - A tool to identify sudo rules' misconfigurations and vulnerabilities within sudo
• CIS Benchmarks Audit - bash script which performs tests against your CentOS system to give an indication of whether the running server may comply with the CIS v2.2.0 Benchmarks for CentOS (only CentOS 7 for now)
• CIS Debian Hardening - Modular Debian 11/12/13 security hardening scripts based on CIS Benchmarks recommendations.
• VPS Security Audit Script - A comprehensive Bash script for auditing the security and performance of your VPS (Virtual Private Server)

Windows

• Microsoft Security Compliance Toolkit 1.0 - set of tools that allows enterprise security administrators to download, analyze, test, edit, and store Microsoft-recommended security configuration baselines for Windows and other Microsoft products
• Microsoft DSC Environment Analyzer (DSCEA) - simple implementation of PowerShell Desired State Configuration that uses the declarative nature of DSC to scan Windows OS based systems in an environment against a defined reference MOF file and generate compliance reports as to whether systems match the desired configuration
• HardeningAuditor - Scripts for comparing Microsoft Windows compliance with the Australian ASD 1709 & Office 2016 Hardening Guides
• PingCastle - Tool to check the security of Active Directory
• MDE-AuditCheck - Tool to check that Windows audit settings are properly configured in the GPO for Microsoft Defender for Endpoint

Network Devices

• Nipper-ng - to check the configuration of network devices (does not seem to be updated)

TLS/SSL

• Qualys SSL Labs - List of tools to assess TLS/SSL servers and clients
• CryptoLyzer - Fast, flexible and comprehensive server cryptographic protocol (TLS, SSL, SSH, DNSSEC) and related setting (HTTP headers, DNS records) analyzer and fingerprint (JA3, HASSH tag) generator with Python API and CLI.
• SSLyze - Fast and powerful SSL/TLS scanning library.
• testssl.sh - Testing TLS/SSL encryption anywhere on any port

SSH

• CryptoLyzer - Fast, flexible and comprehensive server cryptographic protocol (TLS, SSL, SSH, DNSSEC) and related setting (HTTP headers, DNS records) analyzer and fingerprint (JA3, HASSH tag) generator with Python API and CLI.
• ssh-audit - SSH server auditing (banner, key exchange, encryption, mac, compression, compatibility, security, etc)

Hardware - CPU - BIOS - UEFI

• CHIPSEC: Platform Security Assessment Framework - framework for analyzing the security of PC platforms including hardware, system firmware (BIOS/UEFI), and platform components
• chipsec-check - Tools to generate a Debian Linux distribution with chipsec to test hardware requirements

Docker

• Docker Bench for Security - script that checks for dozens of common best-practices around deploying Docker containers in production, inspired by the CIS Docker Community Edition Benchmark v1.1.0.

Cloud

• toniblyx/my-arsenal-of-aws-security-tools - List of open source tools for AWS security: defensive, offensive, auditing, DFIR, etc.

DNS

• IntoDNS.ai - Free DNS and email security scanner. Checks SPF, DKIM, DMARC, DNSSEC, BIMI, MTA-STS configuration and provides AI-powered fix suggestions.

Tools to apply security hardening

• DevSec Hardening Framework - a framework to automate hardening of OS and applications, using Chef, Ansible and Puppet

GNU/Linux

• Linux Server Hardener - for Debian/Ubuntu (2019)
• Bastille Linux - outdated

Windows

• Microsoft Security Compliance Toolkit 1.0 - set of tools that allows enterprise security administrators to download, analyze, test, edit, and store Microsoft-recommended security configuration baselines for Windows and other Microsoft products
• Hardentools - for Windows individual users (not corporate environments) at risk, who might want an extra level of security at the price of some usability.
• Windows 10 Hardening - A collective resource of settings modifications (mostly opt-outs) that attempt to make Windows 10 as private and as secure as possible.
• Disassembler0 Windows 10 Initial Setup Script - PowerShell script for automation of routine tasks done after fresh installations of Windows 10 / Server 2016 / Server 2019
• Automated-AD-Setup - A PowerShell script that aims to have a fully configured domain built in under 10 minutes, but also apply security configuration and hardening
• mackwage/windows_hardening.cmd - Script to perform some hardening of Windows 10
• Windows 10/11 Hardening Script by ZephrFish - PowerShell script to harden Windows 10/11

TLS/SSL

• Mozilla SSL Configuration Generator

Cloud

• toniblyx/my-arsenal-of-aws-security-tools - List of open source tools for AWS security: defensive, offensive, auditing, DFIR, etc.

Password Generators

• How-To Geek - 10 Ways to Generate a Random Password from the Linux Command Line
• Vitux - 8 Ways to Generate a Random Password on Linux Shell
• SS64 - Password security and a comparison of Password Generators

Books

Other Awesome Lists

• Awesome Cybersecurity Blue Team - A curated collection of awesome resources, tools, and other shiny things for cybersecurity blue teams.

Other Awesome Security Lists

(borrowed from Awesome Security)

• Awesome Security - A collection of awesome software, libraries, documents, books, resources and cools stuffs about security.
• Android Security Awesome - A collection of android security related resources.
• Awesome CTF - A curated list of CTF frameworks, libraries, resources and software.
• Awesome Cyber Skills - A curated list of hacking environments where you can train your cyber skills legally and safely.
• Awesome Hacking - A curated list of awesome Hacking tutorials, tools and resources.
• Awesome Honeypots - An awesome list of honeypot resources.
• Awesome Malware Analysis - A curated list of awesome malware analysis tools and resources.
• Awesome PCAP Tools - A collection of tools developed by other researchers in the Computer Science area to process network traces.
• Awesome Pentest - A collection of awesome penetration testing resources, tools and other shiny things.
• Awesome Linux Containers - A curated list of awesome Linux Containers frameworks, libraries and software.
• Awesome Incident Response - A curated list of resources for incident response.
• Awesome Web Hacking - This list is for anyone wishing to learn about web application security but do not have a starting point.
• Awesome Threat Intelligence - A curated list of threat intelligence resources.
• Awesome Pentest Cheat Sheets - Collection of the cheat sheets useful for pentesting
• Awesome Industrial Control System Security - A curated list of resources related to Industrial Control System (ICS) security.