The Practical Linux Hardening Guide

"Did you know all your doors were locked?" - Riddick (The Chronicles of Riddick)

"STATUS:I'm back, work in progress... **** ## Table Of Contents - **[Contributing](#contributing)** - **[Pre install tasks](#pre-install-tasks)** * **[Hard disk encryption](#hard-disk-encryption)** + [Introduction](#information_source-introduction-1) + [Encrypt root filesystem](#eight_pointed_black_star-encrypt-root-filesystem) + [Encrypt /boot partition](#eight_pointed_black_star-encrypt-boot-partition) + [Swap partition](#eight_pointed_black_star-swap-partition) + [Summary checklist](#ballot_box_with_check-summary-checklist-1) - **[Post install tasks](#post-install-tasks)** * **[Bootloader configuration (grub)](#bootloader-configuration-grub)** + [Introduction](#information_source-introduction-2) + [Protect bootloader with password](#information_source-protect-bootloader-with-password) + [Protect bootloader config files](#information_source-protect-bootloader-config-files) + [Summary checklist](#ballot_box_with_check-summary-checklist-2) * **[Disk partitions](#disk-partitions)** + [Introduction](#information_source-introduction-3) + [Separate disk partitions](#eight_pointed_black_star-separate-disk-partitions) + [Mount options: nodev, noexec and nosuid](#eight_pointed_black_star-mount-options-nodev-noexec-and-nosuid) + [Secure /boot directory](#eight_pointed_black_star-secure-boot-directory) + [Secure /tmp and /var/tmp](#eight_pointed_black_star-secure-tmp-and-vartmp) + [Secure /dev/shm](#eight_pointed_black_star-secure-devshm) + [Secure /proc filesystem](#eight_pointed_black_star-secure-proc-filesystem) + [Swap partition](#eight_pointed_black_star-swap-partition-1) + [Disk quotas](#eight_pointed_black_star-disk-quotas) + [Summary checklist](#ballot_box_with_check-summary-checklist-3) * **[Keep system updated](#keep-system-updated)** * [Package management](#package-management) + [Automatic security updates](#automatic-security-updates) + [Remove packages with known issues](#remove-packages-with-known-issues) * [Netfilter ruleset](#netfilter-ruleset) * [TCP wrapper](#tcp-wrapper) * [Users and groups](#users-and-groups) + [Limit su access](#limit-su-access) + [Disable root account](#disable-root-account) + [Logins to system console](#logins-to-system-console) + [Disable shell accounts](#disable-shell-accounts) + [Strong password policy](#strong-password-policy) + [Password aging](#password-aging) + [Previous passwords](#previous-passwords) + [Login failures](#login-failures) + [Protect single user mode](#protect-single-user-mode) * [System path permissions](#system-path-permissions) + [World writable files](#world-writable-files) * [PAM module](#pam-module) * [Limits](#limits) * [Shadow passwords](#shadow-passwords) * [Linux kernel hardening](#linux-kernel-hardening) + [Kernel parameters](#kernel-parameters) + [Network security](#improve-network-security) + [System security](#improve-system-security) * [Remove unused modules](#remove-unused-modules) * [Secure shared memory](#secure-shared-memory) * [IRQ balance](#irq-balance) * [Disable compilers](#disable-compilers) * [Email notifications](#email-notifications) + [Rebooting the system](#rebooting-the-system) * [Backups](#backups) * [External devices](#external-devices) + [Disable USB usage](#disable-usb-usage) - **[Tools](#tools)** * [Logging and Auditing](#logging-and-auditing) + [Auditd](#auditd) + [Tiger](#tiger) + [Aide](#aide) + [Logwatch](#logwatch) * [Other](#other) + [Fail2ban](#fail2ban) + [PSAD](#psad) + [SELinux](#selinux) + [Entropy daemon](#entropy-daemon) + [Centralized authentication service](#centralized-authentication-service) * [Testing tools](#testing-tools) + [Lynis](#lynis) + [Chrootkit](#chrootkit) - **[Services](#services)** * [Disable all unnecessary services](#disable-all-unnecessary-services) + [Common unix print system](#eight_pointed_black_star-common-unix-print-system) + [Summary Checklits](#ballot_box_with_check-summary-checklist-4) * [System services](#system-services) + [OpenSSH](#openssh) + [NTP](#ntp) + [Cron](#cron) + [Anacron](#anacron) + [GnuPG 2](#gnupg2) + [Unattended key generation](#unattended-key-generation) * [DNS services](#dns-services) + [Bind9](#bind9) * [Mail services](#mail-services) + [Postfix](#postfix) * [Web services](#web-services) + [Nginx](#nginx) - [Files and directories permissions](#files-and-directories-permissions) - [Use HTTPS](#use-https) - [Enable HTTP2](#enable-http2) - [Diffie Hellman Ephemeral Parameter](#diffie-hellman-ephemeral-parameter) - [Separate domains](#separate-domains) - [Redirect all unencrypted traffic to HTTPS](#redirect-all-unencrypted-traffic-to-https) - [Enable HTTP Strict Transport Security](#enable-http-strict-transport-security) - [Security related headers](#security-related-headers) + [Apache](#apache) * [Databases](#databases) + [PostgreSQL](#postgresql) + [MySQL](#mysql) + [Redis](#redis) * [Queues](#queues) + [AMQP](#amqp) - **[Deployment](#deployment)** - **[Testing configuration](#testing-configuration)** - **[External resources](#external-resources)** ## Contributing If you find something which doesn't make sense, or one of these doesn't seem right, or something seems really stupid; please make a pull request or please add valid and well-reasoned opinions about your changes or comments. Before add pull request please see **[this](CONTRIBUTING.md)**.