No single tool stops every attack. Firewalls guard the network, anti-malware guards the computer, authentication guards the account and a careful user guards against tricks. Learn each solution, how it works and which threats it helps against.
Data is kept safe by several layers of protection. Firewalls and proxy servers control traffic between a network and the internet. Anti-malware (including anti-virus and anti-spyware) and automatic software updates protect each computer. Authentication (username and password, biometrics, two-step verification) and access levels control who can see what. SSL encrypts data in transit. Privacy settings, and users checking the spelling and tone of messages and the URL attached to a link, protect against people-based attacks. Exam answers must explain how a solution keeps data safe.
Fig. 1: security is built in layers, from the network edge to the computer and its user
Section 01
Proving who you are.
Authentication checks that users are who they claim to be; access levels then decide what each user may do. Try the lab's password tester to see why length and variety matter.
Username and password: only someone who knows the password can log in. Strong passwords are long and mix upper case, lower case, digits and symbols, so a brute-force attack would take far too long. Systems can also lock an account after a few wrong attempts.
Biometrics: uses a unique physical feature, e.g. fingerprint, face, iris or voice recognition. It cannot be forgotten, and is very hard to copy or guess.
Two-step verification: after entering the password, the user must also enter a one-time code sent to their phone or email. A stolen password alone is not enough to log in.
Access levels: different users are given different permissions, e.g. read-only, read and write, or no access to some data. Even if an account is hacked, the attacker can only reach the data that account is allowed to see.
Examiner trap
"Use a password" is not enough for marks. Explain how it helps: e.g. a long, complex password has so many combinations that a brute-force attack would take too long to find it.
Section 02
Guarding the system.
These solutions work in the background, filtering traffic, scanning files and fixing weaknesses.
Solution
How it keeps data safe
Helps against
Firewall
Hardware or software that monitors traffic in and out of a computer or network; it checks it against set rules and blocks traffic that does not meet them, e.g. from blacklisted IP addresses
Hacking, malware, DDoS
Proxy server
Sits between the user and the internet; requests go through it, so the user's IP address is hidden from web servers; it can filter content and block traffic, and absorbs DDoS traffic before it reaches the web server
DDoS, hacking, malicious websites
Anti-malware (anti-virus, anti-spyware)
Scans files and memory, comparing them with a database of known malware signatures and watching for suspicious behaviour; quarantines or deletes what it finds
The operating system and programs install patches automatically, closing security weaknesses as soon as fixes are released, and keep anti-malware definitions up to date
Malware and hacking that exploit known weaknesses
SSL (secure socket layer)
A protocol that encrypts data sent between a browser and a web server, after the server proves its identity with a digital certificate; used by HTTPS
Data interception
Examiner trap
A firewall does not remove malware that is already on the computer; that is the job of anti-malware. A firewall filters traffic.
Stage 1 · Learn
Check what the sim just showed you
Four quick checks. Each correct answer earns XP and records this skill on your profile.
Quick check+10 XP
How does two-step verification keep an account safe?
Quick check+10 XP
In the lab's password tester, which change makes a brute-force attack take longest?
Quick check+10 XP
What does a firewall do?
Quick check+10 XP
Which solution gives different users different permissions to data?
Section 03
Protecting the user.
Many attacks rely on fooling a person, so some of the most important solutions are habits and settings. Use the lab's phishing email to practise what to check before clicking.
Checking the spelling and tone of communications: phishing emails often contain spelling or grammar mistakes, a generic greeting such as "Dear customer", or an urgent, threatening tone ("your account will be closed today"). Spotting these means the user does not click the link.
Checking the URL attached to a link: hover over a link before clicking to see the real address. A misspelt domain, an unexpected domain or a missing https warns of a fake site (phishing or pharming).
Privacy settings: on social media and in browsers, limit who can see personal information and posts. Less information is available for social engineering, and fewer cookies can track the user.
Worked example Match the solution
An email says: "Dear custmer, your acount is locked. Click here within 24 hours." The email claims to be from Brightbank, but the link shows www.br1ghtbank-login.com. Which checks reveal that it is phishing?
Spelling: "custmer" and "acount" are misspelt.
Tone: a generic greeting and an urgent deadline put the user under pressure.
URL: the domain uses the digit 1 in place of the letter i, so it is not the genuine Brightbank site.
Answer: Checking spelling and tone, and checking the URL attached to the link.
Your turn
Which solution helps most against data interception on a payment page, and why?
SSL (HTTPS): it encrypts the data, so intercepted card details cannot be understood.
Stage 2 · Exam
Exam-style questions
Unlocks once the four checks above are done. Worth more XP, written to IGCSE Paper 1 standard.
Finish the four checks above to unlock the exam questions
Exam style+20 XP
Which solution protects data from being understood if it is intercepted?
Exam style+20 XP
Why should software updates be automated?
Exam style+20 XP
How does a proxy server help protect a user?
Exam style+20 XP
Which is an example of biometric authentication?
Skill unlocked
Keeping data safe, mastered.
This skill is now recorded on your profile. Keep the chain going.