Linux Kernel /etc/sysctl.conf Security Hardening

The "sysctl" utility in Linux allows you to modify the kernel parameters at runtime. The parameters are stored in the "/etc/sysctl.conf" file, and you can use this file to harden the security of your system.

Here are some examples of kernel parameters that you can modify in "/etc/sysctl.conf" to improve security:

1. Enable process address space protection:

kernel.randomize_va_space = 2

This parameter enables address space layout randomization (ASLR), which makes it harder for an attacker to predict the memory layout of a process and exploit vulnerabilities.

2. Enable kernel protection from stack-based buffer overflows:

kernel.exec-shield = 1

This parameter enables ExecShield, which is a kernel feature that protects against stack-based buffer overflows by randomizing the memory layout of the stack and limiting the stack size.

3. Enable kernel protection from null pointer dereferences:

kernel.kptr_restrict = 1

This parameter restricts access to kernel pointers, which makes it harder for an attacker to obtain sensitive information about the kernel.

4. Enable kernel protection from timing attacks:

kernel.perf_event_paranoid = 2

This parameter enables kernel protection from timing attacks, which are attacks that rely on measuring the time it takes for the kernel to perform certain operations.