Cyber security: free AQA GCSE Computer Science practice questions

Mistakes to avoid

• Saying a virus and a trojan are the same. A virus attaches itself to a file and spreads when that file is run. A trojan pretends to be useful software so the user installs it.
• Saying phishing and pharming are the same. Phishing tricks the user with a fake message. Pharming redirects the user to a fake website even when they type the correct address.
• Naming a threat when the question asks for a prevention method, or the other way round.
• Saying a firewall removes viruses. A firewall monitors network traffic and allows or blocks it based on security rules; it does not remove malware already on the machine, which is the job of anti-malware software.
• Treating penetration testing as an attack. It is done with permission, to find weaknesses before a real attacker does.
• Forgetting removable media. A memory stick can carry malware onto a system that is otherwise well protected.

Attacks on people rather than technology

Cyber security means the processes, practices and technologies used to protect networks, computers, programs and data from attack, damage and unauthorised access. Social engineering means manipulating people into giving away information or access. Blagging, also called pretexting, is inventing a scenario to persuade a victim to hand over information, such as pretending to be from the IT department. Phishing sends a message that looks like it comes from a trusted organisation to trick the victim into clicking a link or entering credentials on a fake site. Pharming redirects a victim to a fake website even though they typed the correct address. Shouldering is simply watching someone enter a PIN or password.

The malware families

Malware is any software written to cause harm. A virus attaches itself to a file and spreads when that file is run. A trojan pretends to be useful software so the user installs it willingly, then does something harmful once inside. Spyware records what the user does, including keystrokes such as passwords.

Attacks on systems

Weak and default passwords are easy to guess, so longer, more varied passwords and a limit on failed attempts make guessing impractical. Misconfigured access rights let people reach data their job does not need. Removable media can carry malware onto a system, and unpatched or out of date software leaves known weaknesses open to attackers.

The defences you have to name

Penetration testing means attempting, with permission, to gain access to a system in the way an attacker would, to find weaknesses before a real attacker does. The methods to detect and prevent threats that you need to explain are biometric measures, password systems, CAPTCHA, using email confirmations to confirm a user's identity, and automatic software updates. User access levels give each person only the rights they need, so a compromised ordinary account cannot reach everything. Anti-malware software detects and removes known malware. A firewall is a network security device that monitors traffic entering and leaving a network and allows or blocks it based on a set of security rules. Encryption means that data which is intercepted or stolen cannot be read without the key.