Linux Kernel Security Features

Linux Kernel Security Features

The Linux kernel incorporates numerous security features that provide defense against various attack vectors. Address Space Layout Randomization (ASLR) randomizes memory addresses, making exploit development significantly more difficult. This feature, enabled by default in modern distributions, prevents attackers from predicting memory locations necessary for successful exploitation.

Kernel hardening options available through sysctl and compile-time configurations further enhance security. Options like kernel.dmesg_restrict prevent unprivileged users from reading kernel messages, potentially containing sensitive information. The kernel.kptr_restrict setting hides kernel pointers in /proc, preventing information leaks useful for exploit development. Properly configuring these options balances security with operational requirements.

Control groups (cgroups) provide resource isolation and limitation capabilities, essential for container security and system stability. By restricting CPU, memory, and I/O resources, cgroups prevent individual processes from monopolizing system resources. This isolation also provides security benefits by limiting the impact of compromised or malicious processes.

Namespaces enable process isolation by providing separate views of system resources. PID namespaces isolate process trees, network namespaces provide independent network stacks, and mount namespaces create isolated file system views. These features form the foundation for container technologies while also enabling advanced security architectures like sandboxing and privilege separation.