1. Viruses & Security Threats
Unit 1 – Understanding Computer Systems
JMW 2012

2. By the end of this session:
• All of you would be able to explain how viruses
affect computers.
• Most of you should understand how your
identity can be stolen through phishing and
spyware applications.
• A few of you could explore other threats to
data security, e.g. hacking, and actions that can
be taken to minimise risks.

3. Viruses
• Some viruses (or malware) try to gain entry to your computer in a
similar way by pretending to be something else.
• For example, that screensaver you downloaded or game you played
may have a virus contained with it.
• These viruses are sometimes called Trojan Horses.
• Worms are viruses which attach themselves to files on your
computer. Infected files then spread the virus as the worm attaches
itself to other files on the system.
• File sharing websites can often be a source of
viruses. Avoid sharing illegal file-sharing sites
and scan any programs downloaded from the
Internet.

4. How can I protect myself?
• Use a virus scanner to scan any files you
download from the Internet or other
computers.
• Regularly scan your computer’s hard drive for
viruses.
• Keep your virus definitions
up-to-date.

5. Identity Theft
• Phishing emails pretend to be another company in
order to extract personal information, such as
passwords, from users.
• The email asks you to click a link which takes you to a
fake website and then enter your password (which is
then stored by the phishers.)
• Spyware hides on your computer and records
everything you do and passes it on to criminals.
• They can then steal your identity and pretend to be
you – this is called “Identity Theft”

6. How can I protect myself?
• Check the link shown in the email matches the website
you go to when clicked.
• Legitimate emails often use personal data, e.g. first
name, which Phishers don’t have access to.
• Never give out your password details on any website
unless you are 100% sure it is the official website. If in
doubt check the email received with the company before
divulging any information.
• Scan your computer regularly for spyware. Use firewalls
to prevent unauthorised communication from your
computer.

7. Your Task
• Create a poster to raise aware of data security
threats.
• Your poster should:
– Explain the risk
– Give advice on how to minimise the risk
Extra Challenge:
• Explain why every computer should have a firewall installed.
• When you buy something online, how is the debit/credit card data
kept secure?

8. Peer Review of Posters
• Look at the poster of the person sitting next to
you.
• Is it fit for purpose?
– Does it explain at least one of the data security
threats?
– Does it provide advice to minimise the risks?
– Does it stand out? Clear writing?
Identify 2 good things about the poster (2 stars *)
and one area for improvement (1 wish)