Cybersecurity Engineer Tutorials

In this lab, you will learn how to verify if ulimit settings are correctly applied in Linux. You will explore different methods to check resource limits, starting with displaying the current shell's limits using ulimit -a. Following that, you will examine the system-wide configuration file /etc/security/limits.conf to understand how limits are set for users and groups. Finally, you will learn how to verify the actual limits applied to a running process by inspecting its /proc entry. This hands-on approach will provide a comprehensive understanding of how resource limits function and how to troubleshoot related issues in a Linux environment.

In this lab, you will learn how to check the operating state of a Linux system, specifically focusing on how to determine if the system is in single-user mode. You will explore traditional runlevels using the `runlevel` and `who -r` commands, and also examine the default system target in modern `systemd` environments using `systemctl get-default`. This hands-on experience will provide you with practical skills for understanding and verifying the system's operational state.

In this lab, you will learn how to determine if your Linux environment is running on a virtual machine. We will explore three different methods to achieve this: using the `dmidecode` command to inspect system information, utilizing the `virt-what` tool specifically designed for virtualization detection, and examining CPU flags within the `/proc/cpuinfo` file. By the end of this lab, you will be equipped with practical techniques to identify virtualized environments in Linux.

In this lab, you will learn how to determine if your Linux system is 32-bit or 64-bit using command-line tools like `uname -m` and `arch`. You will execute these commands, interpret their output, and inspect binary files to understand your system's architecture and ensure software compatibility.

In this lab, you will learn how to check if specific hardware components are detected in a Linux environment. You will explore practical methods to gather information about your system's hardware, which is essential for troubleshooting, system administration, and understanding your computer's capabilities. Through hands-on steps, you will use the `lscpu` command to examine detailed CPU information, the `lspci` command to list PCI devices, and inspect the `/proc/devices` file to understand detected hardware devices. These techniques provide valuable insights into your system's configuration and help you verify that your hardware is properly recognized by the operating system.

In this lab, you will learn how to check for specific CPU features available on your Linux system. You will explore different methods to inspect CPU information, starting with the fundamental `cat /proc/cpuinfo` command to view detailed CPU specifications and flags. Following the initial inspection, you will utilize the `lscpu` command for a more structured overview of CPU architecture and capabilities. Finally, you will delve into hardware details using `dmidecode` to gain further insights into your system's components, including CPU information.

In this lab, you will learn how to check if swap space is enabled on your Linux system. You will explore three different methods to verify the swap configuration: using the `swapon --show` command to display active swap devices, inspecting the `/proc/swaps` file for detailed information, and examining the `/etc/fstab` file to understand how swap is configured to be enabled at boot time. By completing these steps, you will gain a comprehensive understanding of how to determine the swap status and configuration on your Linux system.

In this lab, you will learn how to check the status and configuration of SELinux on a Linux system. You will use the `sestatus` command, inspect the `/etc/selinux/config` file, and use the `getenforce` command to quickly check the current operating mode. By completing these steps, you will gain a fundamental understanding of how to determine if SELinux is enabled and how it is configured on your system.

In this lab, you will learn how to check for available system updates on a Linux system using the apt package manager. We will cover the essential steps to ensure your system is up-to-date and secure. You will refresh the package list, list upgradable packages, and simulate the upgrade process.

In this lab, you will learn how to determine if a Linux distribution is based on Debian. Understanding the underlying distribution is crucial for package management and system administration. You will use fundamental Linux commands to inspect system files and utilities that provide details about the operating system. Specifically, you will use cat /etc/os-release, lsb_release -a, and cat /etc/apt/sources.list.

In this lab, you will learn how to check if network multicast is enabled and configured on a Linux system. You will explore different methods to verify multicast settings, including examining multicast addresses assigned to network interfaces using the `ip maddr` command, inspecting multicast-related parameters within the `/proc/sys/net` filesystem, and viewing multicast group memberships with the `netstat -g` command. By completing these steps, you will gain practical skills in diagnosing and understanding multicast network configurations in a Linux environment.

In this lab, you will learn how to check if power management is configured on a Linux system. You will explore different methods to verify power management capabilities and settings. Specifically, you will use the pm-is-supported command, examine the /sys/power filesystem, and inspect the logind.conf file.

In this lab, you will learn how to check if kernel performance counters are active in Linux. You will explore how to use the `perf stat` command to measure performance counters for command execution, verify the performance counter configuration within the `/sys/kernel` filesystem, and inspect kernel logs using `dmesg` for messages related to performance counters. This hands-on experience will provide you with the skills to diagnose and understand the status of performance monitoring on your Linux system.

In this lab, you will learn how to check the virtual memory overcommit setting in Linux using the `sysctl` command and exploring the `/proc` filesystem. You will also inspect `/etc/sysctl.conf` to understand persistent configuration. This lab provides hands-on experience verifying and understanding kernel overcommit settings.

In this lab, you will learn how to check if network bonding is configured on a Linux system. Network bonding combines multiple network interfaces for increased bandwidth and redundancy. You will explore three key methods: examining the /proc/net/bonding filesystem, using the ip link command, and inspecting configuration files in /etc/network.

In this lab, you will learn how to check if Non-Uniform Memory Access (NUMA) settings are applied in Linux. Understanding NUMA is crucial for optimizing performance on multi-processor systems. Through hands-on steps using `numactl`, `lscpu`, and `/proc/numa`, you will verify and inspect your system's NUMA configuration.

In this lab, you will learn how to check if kernel lockdown mode is active in Linux. Kernel lockdown is a security feature that restricts certain kernel capabilities to enhance system security. You will examine the kernel's lockdown status, verify lockdown messages in the kernel ring buffer, and inspect security settings.

In this lab, we will explore how to check and understand kernel memory limits in Linux. We will focus on the vm.overcommit_memory setting, which controls how the kernel handles memory allocation requests. Through hands-on steps, you will learn to use the sysctl command, verify settings in /proc/sys/vm, and identify configuration files in /etc/sysctl.d. This lab provides practical experience in managing and understanding Linux memory behavior.