Linux hardening with sysctl

Linux Sysctl Hardening The GNU/Linux kernel powers a lot of systems, from big mainframes to the Android device in your pocket. If you want to achieve more security on your Linux systems, it would make sense to start hardening there, right? While securing the kernel looks easy at first sight, there is more to it than initially meets the eye. Let’s have a look at some kernel options and defining the best sysctl values for Linux systems. Why Invest Time in […]

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Kernel hardening: Disable and blacklist Linux modules

Disable and black Linux kernel modules The Linux kernel is modular, which makes it more flexible than monolithic kernels. New functionality can be easily added to a run kernel, by loading the related module. While that is great, it can also be misused. You can think of loading malicious modules (e.g. rootkits), or unauthorized access to the server and copy data via a USB port. In our previous article about kernel modules, we looked at how to prevent loading any […]

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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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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 kernel security and how to improve it

Linux kernel security Every system is as strong as its weakest link. In the case of an operating system a weakness in the kernel often means a total compromise. Therefore we focus in this article on Linux kernel security, what we can do and where to look for. Configuration of the kernel To view or configure security related parameters of the kernel, there is the /etc/sysctl.conf file. This file stores the parameters and is read during boot time. However we […]

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