Cyber Security revision guide

What cyber security protects

Cyber security is the set of processes and practices that protect computer systems, networks, programs and data from attack, damage or unauthorised access.

Social engineering

Social engineering attacks the people rather than the technology, persuading someone to hand over information or access. A system can be technically secure and still be entered this way.

Phishing

Phishing sends messages that appear to come from a trusted organisation, to trick the reader into giving away details or opening an attachment. Unexpected attachments and links are the common route in.

Malware

Malware is software written to damage a system or steal from it.

• A virus attaches itself to a file and spreads when that file is run.
• A worm spreads by itself across a network.
• A Trojan is disguised as something useful.
• Ransomware locks the data and demands payment.
• Spyware secretly records what the user does.

Other forms of attack

• A brute force attack tries many possible passwords in turn.
• A denial of service attack floods a service until it cannot respond.
• Data interception captures data as it crosses a network.
• SQL injection enters database commands into an input box that fails to check what it accepts.

Penetration testing

Penetration testing is an authorised attempt to break into a system in order to find its weaknesses before someone else does.

Security measures

No single measure is enough, so several are used together:

• strong passwords, which are long and not reused;
• biometric checks such as a fingerprint;
• CAPTCHA, to tell a human from an automated program;
• a firewall, which filters traffic entering or leaving a network;
• anti-malware software, which detects and quarantines malicious files;
• access levels, so each user reaches only what their role requires;
• regular backups and software updates.

Encryption

Encryption converts readable plaintext into ciphertext using a key. Without the key the data is unreadable.

Encryption does not stop data being intercepted or stolen. It makes what is taken useless.