Firewalls, anti-malware, access levels, strong passwords and authentication, biometrics, updates, backups, penetration testing, and the weak points attackers look for.
What you will learn
- Match each threat to a defence
- Spot weak points and close them
- Apply a password policy
- Read firewall rules and access levels
- Explain two-factor authentication
Layers of defence
Much of what an organisation must protect is personal data: data about an identifiable living person, such as names, addresses and health records.
| Defence | Protects against |
|---|---|
| Firewall: checks traffic in and out against rules | unauthorised access, some DoS |
| Anti-malware, kept updated | viruses, worms, trojans, spyware |
| User access levels: only what each job needs | insiders and stolen accounts doing damage |
| Strong passwords, lockout, two-factor authentication | brute force and stolen passwords |
| Input validation and parameterised queries | SQL injection |
| Encryption | interception |
| Software updates (patches) | attacks on known security holes |
| Backups | ransomware, deleted or damaged data |
| Staff training and policies | phishing, blagging, shouldering |
| Physical security (locked rooms) | theft and tampering |
Anti-malware recognises known malware by its signature, a pattern of code that identifies it. New malware appears all the time, so the signatures must be updated regularly. Ransomware can encrypt anything it can reach, so backups are kept apart from the network.
A firewall works through a list of rules. Each kind of traffic uses a numbered port: web pages (HTTP) use port 80 and secure web pages (HTTPS) port 443.
The firewall checks each packet against the rules from the top and uses the first rule that matches. The last rule usually catches anything else: if it says Block, every port not named above it is blocked.
Penetration testing: authorised experts attack the system on purpose to find weaknesses before criminals do.
The rest of this lesson and its 12 practice questions are locked.
In this lesson
- Layers of defence
- Authentication
- Weak points and checks
- Try it: Match threat to defence
12 practice questions, marked as you go; about 20 minutes in all.
Key terms
Signature, First, Authentication, Know, Have, Are, Biometrics, CAPTCHA, Automatic updates, Removable media
In this unit: Cyber security
Malware and social engineering, brute force, denial of service, SQL injection and interception, and the defences against them, with Caesar ciphers and password maths.