Kernel

Sysctl: ipe.success_audit

Sysctl key ipe.success_audit key is used to define if audit events should be created when using the Linux security module IPE (Integrity Policy Enforcement).

Sysctl: ipe.enforce

The sysctl key ipe.enforce defines the mode of the Linux security module IPE (Integrity Policy Enforcement). Learn about the possible values and their meaning.

Ipe

The sysctl settings starting with ipe define the configuration of IPE (Integrity Policy Enforcement) module. Learn about the settings and possible values.

What is the difference between /dev/random and /dev/urandom?

Learn the difference between Linux kernel random sources /dev/random and /dev/urandom, and when to use which one. Spoiler: probably /dev/urandom.

Capabilities

Linux capabilities define the implementation of privileged tasks. This area collect everything related to Linux capabilities and what they do.

Overview of Linux capabilities

An overview of the available Linux capabilities that allow processes to perform privileged actions.

Overview of Linux syscalls

An overview of the available Linux syscalls, or system calls, that allow processes to communicate with the kernel.

How to see kernel messages with journalctl

Linux systems using systemd store kernel events in the journal logs. Show these entries with the '--dmesg' or '-k' option, optionally with a date.

Sysctl net.*

The kernel has a wide range of network settings. Learn about the sysctl command and the values related to the network class.

Sysctl: net.ipv4.ip_forward

The sysctl key net.ipv4.ip_forward key is used to define IP forwarding of IPv4 network packets. Learn about the possible values of this key and their meaning.

Sysctl: kernel.perf_event_paranoid

Secure the Linux kernel with the help of the sysctl kernel.perf_event_paranoid key, including the possible values and their meaning.

What is a tainted kernel

The Linux kernel is marked tainted when a specific event happened that could impact reliable troubleshooting of kernel issues. Learn about the relevant events.

How to find the specific cause of a tainted kernel

The Linux kernel can mark itself as being 'tainted'. Learn what it means when the Linux kernel is tainted and in particular the underlying cause.

Kernel: Frequently Asked Questions

Frequently asked questions about the Linux kernel and kernel security.

Sysctl

Learn about the sysctl command and how it can help with kernel tunables to alter the system configuration and perform additional security hardening.

Sysctl kernel.*

The Linux kernel has a range of settings that influence the behavior of the kernel itself. Learn about sysctl settings and values related to the kernel class.

Kernel.tainted

Improve the Linux security by understanding and configuring the sysctl kernel.tainted key, including the possible values and their meaning.

Kernel

The Linux kernel consists of many components. Learn from topics related to kernel itself, its configuration, up to security and querying information.

Linux hardening with sysctl settings

The Linux kernel can be secured with the help of kernel tunables called sysctl keys. Learn how system hardening principles can be applied using sysctl.

Kernel hardening: Disable and blacklist Linux modules

The Linux kernel provides modular support to allow loading kernel modules during runtime. To prevent security issues, learn how to disable or blacklisting.

Increase kernel integrity with disabled Linux kernel modules loading

The Linux kernel can be configured to disallow loading new kernel modules. Learn how this may help and how to configure this behavior in the sysctl settings.

How to check if your Arch Linux system needs a reboot

Want to check if a reboot of the system is needed on Arch Linux? Here is how that can be done including the relevant commands.

Protect against ptrace of processes: kernel.yama.ptrace_scope

Using the Linux Security Module (LSM) Yama we can protect the system against the usage of ptrace. The sysctl key kernel.yama.ptrace_scope sets the behavior.

How and why Linux daemons drop privileges

By dropping privileges a process can be better protected against attacks. Learn how this applies to Linux systems and software.

Linux kernel security and how to improve it

Every system is as strong as its weakest link, especially the system kernel. This article explains Linux kernel security, what we can do and how to do so.