The Most Influential Linux Security Blogs

Linux Security Blogs Finding quality blogs about Linux security can be challenging. We made an effort to seek the best and most influential blogs on the internet. What makes it influential? It should have quality articles, regularly updated and tailored to Linux or UNIX security. The countless “How to” websites are skipped. Months of searching and reading resulted in a list of blogs, sorted by category. If you are interested in the developments on Linux security, add them to your […]

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How Linux Security Fails to be Simple

Linux Security Should be Simple, Right? Why that is not a reality, and we might never achieve it. Linux gained great popularity over the last 10 years, powering our servers and smartphones. With all the efforts put in creating more secure software, it seems installing security updates will remain a weekly task. Will this ever change? Security is Hard Properly securing a system means different things for different people. So let’s take the assumption that every system has a particular […]

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Increase kernel integrity with disabled Linux kernel modules loading

Increasing Linux kernel integrity Disable loading kernel module on Linux systems The Linux kernel can be configured to disallow loading new kernel modules. This feature is especially useful for high secure systems, or if you care about securing your system to the fullest. In this article, we will have a look at the configuration of this option. At the same time¬†allowing legitimate kernel modules to be loaded. Disable kernel modules Newer kernel modules have a sysctl variable named kernel.modules_disabled. Sysctl […]

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Password Security with Linux /etc/shadow file

Password Security on Linux Using the /etc/shadow file Linux systems use a password file to store accounts, commonly available as /etc/passwd. For additional safety measures, a shadow copy of this file is used which includes the passwords of your users. Or actually hashed password, for maximum security. An example of a password entry in /etc/shadow may look like this: user1:$6$6Y/fI1nx$zQJj6AH9asTNfhxV7NoVgxByJyE.rVKK6tKXiOGNCfWBsrTGY7wtC6Cep6co9eVNkRFrpK6koXs1NU3AZQF8v/:16092:0:99999:7::: For proper display, let’s split this up in several fields: user1 $6$6Y/fI1nx$zQJj6AH9asTNfhxV7NoVgxByJyE.rVKK6tK<truncated> 16092 0 99999 7 <nothing> <nothing> Field explanations […]

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An Introduction Into Linux Security Modules

An Introduction Into Linux Security Modules Background Like normal kernel modules, security modules extend the basic functionality of the Linux kernel. The need for a modular structure was proposed when SELinux was being introduced. There was a little discussion to use modules or not, as SELinux was the only one being available. Some people proposed apply it as a kernel patch, but in the end Linux creator Torvalds, decided to make this type of functionality modular. The first security module […]

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Monitoring Linux File access, Changes and Data Modifications

Monitoring File access, Changes and Data Modifications   Linux has several solutions to monitor what happens with your data. From changing contents to who accessed particular information, and at what time. For our auditing toolkit Lynis, we researched and tested several solutions over the last few years. In this article we have a look at these solutions to monitor file access, changes and modifications to the data and beyond. What is Data? Data is a collection of bits, ordered in […]

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How to check if your Arch Linux system needs a reboot

Arch Linux reboots How to check if a reboot is needed By default Arch will install the kernel in /boot with the name vmlinuz-linux. To determine if the system is running the latest kernel, we can compare the running kernel and the one on disk. Running kernel One way to determine the running kernel is with the uname command. By default installed and with the -r parameter it will provide the kernel release version. [root@archlinux ~]# uname -r 3.17.4-1-ARCH Kernel […]

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Linux Capabilities 101

Linux Capabilities 101 Tutorial about how capabilities work in Linux Even seasoned Linux administrators may not see capabilities a lot in their daily duties, but they are still used all the time. This features was added to Linux 2.2 and gave us new possibilities regarding security. In this guide we have an in-depth look on how can leverage them to increase security. The problem It is good to know why capabilities were implemented at the first place. Let’s assume we […]

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