Postfix Hardening Guide for Security and Privacy

Postfix Security and Privacy Postfix is a common software component on servers for receiving or sending email. It has a lot of configuration options available, including those to improve your Postfix security. This security and privacy guide looks into Postfix hardening. After you are finished, your system will have improved defenses against spam, abuse, and leaking sensitive data. Time to start! Table of Contents Why Postfix hardening Preparation Test the existing Postfix configuration Backup your Postfix configuration Find your Postfix version […]

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Ubuntu Hardening Guide for Desktops and Servers

Ubuntu system hardening: Quick and Secure The system hardening process of a system is critical during and after installation. It helps the system to perform its duties properly. This blog post shows you several tips for Ubuntu system hardening. It will dive into the most critical steps to take first. Then more specific hardening steps can be added on top of these. As most security guides only tell you what to do, we will also go into more detail on […]

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Linux Security Guide (extended version)

Linux Security Guide (extended version) With so many articles about Linux security on the internet, you may feel overwhelmed by how to properly secure your Linux systems. With this guide, we walk through different steps, tools, and resources. The main goal is to have you make an educated choice on what security defenses to implement on Linux. For this reason, this article won’t show any specific configuration values, as it would implicate a possible best value. Instead, related articles and […]

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Discover to which package a file belongs to

Related Packages and Files Sometimes you want to know the related package of a file, before installation, or when it is already there. This is of great help during system hardening or general system cleanups. In this article we have a look at several ways to determine the relationships between files and the package they belong to. We have gathered this information for multiple Linux distributions. CentOS, Fedora, RHEL Show files for RPM packages rpm -qlp /path/to/file.rpm Show files for packages on […]

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Linux system hardening: adding hidepid to /proc mount point

Hiding processes for other users When looking in /proc you will discover a lot of files and directories. Many of them are just numbers, which represent the information about a particular process ID (PID). By default, Linux systems are deployed to allow all local users to see this all information. This includes process information from other users. This could include sensitive details that you may not want to share with other users. By applying some file system configuration tweaks, we can change […]

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Linux Security Guide for Hardening IPv6

Linux Security Guide for Hardening IPv6 Version 6 of Internet Protocol is now 20+ years available. You would think it is widely available now, right? Not exactly. Still many internet providers don’t have it deployed for their customers. Hosting companies are not always eager to deploy it either. Mostly because of lacking knowledge. To get at east more knowledge shared on the security side of IPv6, we have crafted this guide. Hopefully it will be a practical guide for your […]

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Tiger is History, Long Live Modern Alternatives!

The History and Alternatives to the Tiger Security Tool Recently I saw some tweets showing up from an old friend: Tiger. Surprised to see it being promoted, as I know the tool for years, but never seen any new releases in the last years. Both are actually a shame. An outdated tool is usually of lower value. Promoting old tools might actually disappoint others and harm the initial trust in the software. History of Tiger In its day, the tool […]

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Security Defenses to Fortify your Linux Systems

How to Fortify your Linux Systems Create a Linux security fortress; implementing security defenses using towers, bridges, and guards. Still many companies have difficulties implementing basic security measures. Even after years of websites being defaced, and customer records stolen, the same mistakes are made over and over again. While this all might sound like an unsolvable situation, information security is getting attention from more people. If you are responsible for the system management of Linux systems, ignoring security is no […]

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