Cyber security: malware, social engineering and attacks
Attackers target both computers and the people who use them. This page covers the main kinds of malicious software, the tricks used on people, common attacks on systems, and the defences that stop each one.
Part 1 of 3: Learn it
In short
- Malware is software written to cause harm: viruses, worms, trojans, ransomware and spyware.
- Social engineering tricks people into giving away information or access, as in phishing.
- Defences include anti-malware software, firewalls, strong passwords, encryption, updates and staff training.
Where this is in your specification
Spec points: AQA 3.6.1 and 3.6.2, OCR 1.4.1 and 1.4.2, Edexcel Topic 5
| Board | Topic: Cyber security |
|---|---|
| AQA 8525 | 3.6 |
| Edexcel 1CP2 | Topic 5 (cyber security) and Topic 2 (encryption) |
| OCR J277 | 1.4.1 and 1.4.2 |
| Eduqas C500 | 3 Networking and cybersecurity |
| Cambridge IGCSE 0478 | 2.3, 5.3 |
| National 5 C816 75 | Computer systems: security precautions |
Types of malware
| Malware | What it does |
|---|---|
| Virus | attaches to a file and spreads when that file is run or copied |
| Worm | copies itself across a network on its own, without a host file |
| Trojan | pretends to be useful software but carries a harmful payload |
| Ransomware | encrypts the victim's files and demands payment |
| Spyware | secretly records activity, such as keystrokes, and sends it on |
Social engineering
- Phishing: fake emails or messages that look genuine and ask you to click a link or enter details.
- Blagging (pretexting): making up a believable story, often on the phone, to get information.
- Shouldering: watching someone type a PIN or password.
- Pharming: redirecting a user from a real website to a fake one.
Attacks on systems
- Brute force: trying every possible password until one works. Stopped by long passwords and locking accounts after a few failed attempts.
- Denial of service (DoS): flooding a server with requests so real users cannot get through.
- SQL injection: typing SQL code into an input box so the database runs it. Stopped by validating and sanitising input.
- Data interception: capturing data as it travels across a network. Made useless by encryption.
Defences
Anti-malware software scans for and removes known malware. A firewall checks traffic coming in and going out and blocks anything not allowed. User access levels limit who can see or change data. Installing updates fixes known weaknesses. Penetration testing pays experts to attack a system on purpose to find its weak points first. Multi-factor authentication needs a second proof of identity, such as a code sent to a phone.
What is the difference between a virus and a worm?
Show the answer
A virus needs a host file to spread; a worm spreads across a network on its own.
Part 2 of 3: See it worked
Worked examples
Example 1
How many different 4-digit PINs are there, and how many 8-character passwords can be made from upper and lower case letters and digits?
- PIN: 10 choices for each of 4 digits, 10⁴ = 10 000
- Password: 26 + 26 + 10 = 62 choices for each of 8 characters
- 62⁸ = 218 340 105 584 896
Answer: 10 000 PINs against about 2.2 × 10¹⁴ passwords, which is why longer passwords with more types of character resist brute force.
Example 2
An email that looks as if it is from a bank asks the reader to confirm their account details through a link. Name the threat and give two ways to protect against it.
- It is pretending to be genuine to get personal details: phishing
- Protection: staff training to spot fake senders and links
- Protection: email filters that block suspicious messages
Answer: Phishing; defend with training and email filtering (also never entering details from a link).
Common mistakes
- Using virus to mean any malware.
- Saying a firewall removes viruses. It controls network traffic; anti-malware software removes malware.
- Saying encryption stops data being intercepted. It stops intercepted data being understood.
- Giving "use a password" as a defence without saying it should be strong or changed.
What is blagging?
Show the answer
Inventing a believable scenario to persuade someone to give away information.
Part 3 of 3: Test yourself
Check yourself
Answer each one in your head or on paper first, then open it to check.
What is the difference between a virus and a worm?
A virus needs a host file to spread; a worm spreads across a network on its own.
What is blagging?
Inventing a believable scenario to persuade someone to give away information.
How can SQL injection be prevented?
By validating and sanitising everything a user types before it reaches the database.
Jobs that use this
- IT security co-ordinator (se abre en otra pestaña)
- Network engineer (se abre en otra pestaña)
- Systems analyst (se abre en otra pestaña)
Each link opens the job profile on the National Careers Service (England). In the rest of the UK: My World of Work (Scotland), Careers Wales, nidirect careers (Northern Ireland).
Estos apuntes están en inglés porque siguen los programas de examen del Reino Unido.
Full lessons and marked practice for this course are coming soon to Brainlag Learn. See courses