Imagine someone has a padlock with a 4-digit code, and you don't know the combination. The dumbest — but sometimes effective — way to open it is to just try every single combination: 0000, 0001, 0002... all the way to 9999. That's a brute-force attack: an attacker automates guessing, trying huge numbers of password combinations per second until one works.

A smarter cousin of this is the dictionary attack. Instead of trying every possible combination, it only tries words and phrases people actually use as passwords — password, 1234, qwerty. Because so many real people pick predictable passwords, this shortcut cracks accounts far faster than a pure brute-force search.

Data travelling across a network is like a postcard, not a sealed envelope — if it isn't encrypted, anyone who can "see" the traffic can read it. A packet sniffer is a tool (hardware or software) that captures data packets moving across a network, letting a thief read usernames, passwords, and other sensitive information as it travels.

This is especially dangerous on public Wi-Fi, where an attacker on the same network can sniff traffic between your device and the router.

Picture a small shop with one till. Now imagine a thousand people crowd the entrance at once, not to buy anything, but just to block real customers from getting in. That's a Distributed Denial of Service (DDoS) attack — a server gets flooded with requests from many different devices at once until it can't keep up, and genuine users can't access the service.

The word "Distributed" is key: the flood comes from many devices spread across the internet (often infected computers called bots, controlled remotely without their owners knowing). This makes it very hard to trace the attack back to one person, because the traffic looks like it's coming from thousands of innocent machines.

Hacking is the umbrella term for identifying and exploiting weaknesses in a system to gain unauthorised access. It's not one specific technique — it's the goal (getting in without permission), and hackers use whatever weakness is available: unpatched software, out-of-date anti-malware, weak passwords, and so on.

Once in, the motive varies: stealing data, installing malware, or simply disrupting operations.

Malware (malicious + software) is any software deliberately created to cause harm. Think of it as a family of six related but distinct threats — the exam loves to test whether you can tell them apart, so focus on the one detail that makes each one unique.

Pharming is sneakier than phishing because the user doesn't even have to click a suspicious link in the moment — they type a completely normal, correct web address, and still end up on a fake site. How? The attacker has already tampered with the "directory" that translates web addresses into IP addresses (DNS settings), or changed the browser's settings, or planted malware earlier via a link the user clicked.

Phishing is "fishing" for victims: fraudulent emails or SMS messages sent to a huge number of people at once, pretending to be from a bank, company, or trusted source, trying to trick the user into clicking a link and handing over login details.

Every technical defence in the world is useless if a person can simply be talked into giving away the keys. Social engineering exploits weaknesses in a system by targeting the people who use or have access to it — not the code.

• Fraudulent phone calls: pretending to be someone else to get account details.
• Pretexting: a fake message pretending to be from the government or HR, tricking someone into giving out confidential data.

People become "the weak point" through everyday carelessness: not locking server room doors, not logging off unattended devices, sharing passwords, not encrypting data, not keeping software updated.

Not everyone on a network should be able to see or touch everything. Access levels make sure users can only reach what they actually need, based on their role, responsibility, or clearance level.

"Anti-malware" isn't one program — it's a combination of software types working together: anti-virus, anti-spam, and anti-spyware. Together they scan email attachments, websites, and downloaded files for problems.

The key mechanism: anti-malware keeps a list of known malware signatures (a bit like a "wanted poster" of known criminals) and blocks anything matching one immediately. That's exactly why it needs to check for updates regularly — new malware appears constantly, and a database of "known criminals" from six months ago won't catch today's threats.

Authentication is about proving you are who you say you are — this matters because bots can submit data into online forms just as easily as humans can, so a system needs a way to tell them apart.

• Usernames and passwords — the classic method.
• Multi-factor authentication (MFA) — a second proof, e.g. a code sent to your phone.
• CAPTCHA — a task easy for a human but hard for a bot (e.g. "select all squares with a wind turbine").

Biometrics

Biometrics authenticate using unique physical characteristics — fingerprints, facial recognition, iris scans. These are considered more secure than passwords for very concrete reasons:

Software updates often exist specifically to patch security flaws that attackers already know how to exploit. Automatic updates remove the human "I'll do it later" failure point, ensuring fast deployment as soon as a fix is released — closing the window of vulnerability as quickly as possible.

Sometimes the best defence isn't technical at all — it's simply reading carefully. Phishing scams tend to give themselves away through:

• Rushed quality — mass fraudulent messages prioritise quantity over quality, so they often have spelling/grammar errors.
• Urgency — a panicked or pressuring tone is a classic red flag.
• Lack of professionalism — genuine companies proofread their communications.

Checking the actual URL behind a link is equally important — hackers register look-alike domains such as http://amaz.on.co.uk/ instead of http://amazon.co.uk/. Always check the real address before clicking.

A firewall is like a security guard standing at the door of a network, checking every piece of traffic (incoming and outgoing) against a rulebook, and only letting through what's legitimate.

Prevents: hackers, malware, and unauthorised access to the network.

Privacy settings control how much personal information is shared online. They're a key defence against identity theft and other online fraud — and they should be reviewed regularly, since default settings often share more than users realise.

A proxy server sits between the user and the internet, hiding the user's IP address and location — making it harder for hackers to track them. It can also act as a firewall, filtering web traffic against set criteria and blocking malicious content (with a warning sent to the user), directing threats away from the actual server.

SSL is the security protocol that makes secure online transactions possible — it's why you look for the padlock icon when entering card details. It encrypts data transmitted over the internet, preventing eavesdropping and interception.