Your home lab: what you are building and why

(Quick review first: confidentiality, integrity and availability are the three questions, they trade off against each other, and choosing which matters most is a deliberate decision.)

Why a lab

You cannot learn to defend systems by reading about them, and you certainly cannot practise on systems that matter. So you build your own — a small, disposable network living inside your laptop, where you can break things freely.

Everything for the next twelve weeks happens here. By Week 8 this lab gains a Wazuh SIEM watching it; by Week 12 it is a small monitored network you secure and defend. Build it properly this week and the rest of the course is straightforward. Skip it and nothing after Week 3 will work.

Virtual machines

A virtual machine is a whole computer running as software inside your real computer. It has its own operating system, disk, and network connection, and it believes it is a real machine. Your actual laptop is the host; each virtual computer is a guest.

This is exactly what you want, for three reasons:

1. Isolation. A guest can be thoroughly broken without touching your host. Your coursework, photos and banking stay untouched.
2. Snapshots. You can freeze a VM's exact state and roll back to it in seconds. Broke it beyond repair? Restore and continue.
3. Multiple machines. Real security involves several computers talking to each other — attacker, victim, monitoring server. You need more than one, and buying three laptops is not reasonable.

You will use VirtualBox: free, open-source, and runs on Windows, macOS and Linux.

What you are building

Two guests this week, joined by a third in Week 8:

• Ubuntu Server 22.04 LTS — Linux, no graphical desktop, driven entirely from the command line. The majority of the world's servers look like this, and most of what you monitor in your career will be Linux.
• Windows 10 or 11 (evaluation edition) — Microsoft provide free time-limited images for exactly this purpose. Most staff desktops in real organisations are Windows, so most attacks that reach people land here.
• Wazuh server (from Week 8) — the SIEM that watches the other two.

They sit on a private virtual network that can see each other but is walled off from your home network. Attack traffic stays inside the lab, which is both good practice and the reason none of this breaks the one rule.

Snapshots: the habit that saves your term

Learn this now, because the learners who struggle are always the ones who skipped it.

A snapshot records a VM's complete state — disk, memory, settings — at a moment in time. Restoring returns the machine to exactly that moment. It takes seconds.

The habit: take a snapshot before every lab, and name it usefully. clean-install-before-week-3 tells you something; Snapshot 1 does not.

When a lab goes wrong — and labs go wrong, that is what they are for — you restore and try again, instead of losing an evening rebuilding a VM or, worse, quietly falling behind and hoping nobody notices.

Expect friction

The first lab is the most frustrating one in the course, for everybody. Installing operating systems involves waiting, and virtualisation has a few well-known traps:

• Virtualisation disabled in BIOS. The most common problem by far. VirtualBox will refuse to start a 64-bit guest, often with an unhelpful error. The fix is a BIOS setting — usually called Intel VT-x, AMD-V, or SVM Mode. It hits several people in every cohort. It is not a sign you are bad at this.
• Hyper-V on Windows 11. Microsoft's own virtualisation can conflict with VirtualBox, causing VMs to run at unusable speed or not at all.
• Not enough RAM. Two VMs plus your host genuinely needs 16 GB. This is the requirement with no workaround.

Bring these to your instructor early. Everyone hits at least one. Sitting silently with a broken lab for three weeks is the single most reliable way to fail this course.

Try it now

Before the lab session, get the downloads going — they are large and slow, and doing this in the session wastes it:

1. Download VirtualBox for your host OS from virtualbox.org.
2. Download the Ubuntu Server 22.04 LTS ISO from ubuntu.com/download/server (about 2 GB).
3. Download a Windows 10/11 evaluation ISO from Microsoft's Evaluation Center (about 5 GB).

Start all three now, on a connection you are not paying for by the megabyte. Then confirm your RAM, virtualisation setting and free disk from the first lesson.