4.2 network security

Question 1

What is network security?

Answer 1

The protection of a network from external and internal threats such as viruses, hacker attacks, data interception, theft etc.

Question 2

What is a security threat?

Answer 2

An incident - malicious or unintended - that causes disruption, damage or data loss.

Question 3

What is a virus?

Answer 3

A piece of malicious code that attaches itself to a legitimate program and is activated when the ‘host’ program is on, it can cause severe damage to data.

Question 4

What is a hacker?

Answer 4

A seeker and exploiter of security vulnerabilities in code in order to gain unauthorised access to a computer system or network.

Question 5

What is ransomware?

Answer 5

An attack on a network in which data stored on a server is encrypted, making it unreadable. To be decrypted, the victim must pay a ransom.

Question 6

What is data integrity?

Answer 6

The reliability and trustworthiness of data.

Question 7

What does DOS stand for?

Answer 7

Denial of Service.

Question 8

What is a DOS attack?

Answer 8

An attack on a network that attempts to prevent legitimate users from accessing its services. It’s done by taking the network offline. Effective backup and recovery procedures are needed to prevent them.

Question 9

What is backup and recovery?

Answer 9

The process of making backup copies of data and storing them in a separate location to the live working environment (e.g the cloud) so they can be recovered in the event of data loss or damage.

Question 10

What is ethical hacking?

Answer 10

Essentially good hacking. The process of looking for weaknesses in software and systems so that they can be addressed. Ethical hackers usually work on behalf of an organisation, carrying out simulated hacking attacks on its network to uncover any vulnerabilities.

Question 11

What is penetration testing?

Answer 11

a.k.a. ‘pen testing’ is the uncovering of vulnerabilities that could be exploited by a criminal by an ethical hacker (white-hat hackers).

Question 12

What is social engineering?

Answer 12

An attack that exploits how people behave and respond to certain situations in order to trick them into revealing personal information, usually used by an ethical hacker to test how easily tricked legitimate users of the network can be.

Question 13

What is the goal of network security?

Answer 13

To protect a network and data from internal and external security threats, such as incidents which cause disruption, damage or data loss.

Question 14

List and briefly describe the three important principles underpinning data security?

Answer 14

• Confidentiality: If sensitive data gets stolen from an organisation, it could stop or slow. Only authorised personnel should access it.
• Correctness: Data is useless if wrong. It can be jeopardised intentionally or accidentally; so data access must be controlled.
• Availability: Networks can go offline. Criminals can dish out DOS attacks, taking them offline. Backup and recovery is needed to prevent damage.

Question 15

What is data integrity?

Answer 15

The reliability of data. It can be jeopardised (un)intentionally. It must be checked, secured and protected to maintain data security.

Question 16

What is social engineering?

Answer 16

Testing done by ethical hackers to test out employees’ security awareness. It exploits how people behave and respond to certain situations in order to trick them into revealing personal information.

Question 17

What is access control?

Answer 17

Control of who can log into a network and determines which legitimate/authorised users can see and do on the network.

Question 18

What is authentication?

Answer 18

The process of checking the identity of an individual attempting to gain access to a network?

Question 19

What is multi-factor authentication?

Answer 19

An extra level of security. A user must provide:
- A piece of knowledge
- A physical artefact
- A physical attribute

Question 20

What is the principle of least privilege?

Answer 20

Employees are only given the permissions and administrative rights needed to do their job.

Question 21

What are file permissions?

Answer 21

Control of the ability to read, write, execute and delete files.

Question 22

What is physical security?

Answer 22

Controlling access to critical parts of a network using physical methods rather than software.

Question 23

What is malware?

Answer 23

Malicious software designed to gain unauthorised access to a computer system in order to cause damage, disrupt its functioning or collect information without the users’ knowledge.

Question 24

What is encryption?

Answer 24

The process of turning information into a form that only the intended recipient can decode. It keeps data secure by using a key to encode the data, only someone with the key can decrypt.

Question 25

What is a firewall?

Answer 25

A network security system that inspects incoming and outgoing data traffic and uses a set of rules to decode the data and figure out what data to allow through from on side to the other.

Question 26

Give three examples of authentication.

Answer 26

• username and password
• algorithms and code
• multifactor authentication

Question 27

List 3 criteria (with examples) a user must provide to gain access to a network using multi-factor authentication.

Answer 27

• A piece of knowledge (ID, password or pin)
• A physical artefact (identity pass)
• A physical attribute (fingerprint or voice)

Question 28

List and explain four types of file permissions.

Answer 28

• Read: users can open the file and read its contents, but can’t modify or delete it.
• Write: Users can read and modify the file, but can’t delete it.
• Execute: Users can execute a program file.
• Delete: Users can delete a file.

Question 29

Give 3 examples of firewall rules.

Answer 29

• Rule which stops certain protocols from being used to prevent the organisation’s data from being potentially copied to an external server
• Rule which blocks data coming/going from/to certain network addresses
• Rule which stops attempts of hacking the internal networks’ servers by disallowing data that matches the pattern an attacker would use

Question 30

Give four suspicious activities that firewalls could block.

Answer 30

• Downloading viruses while browsing online
• Emailing sensitive data to themselves or to someone else outside of the organisation
• Visiting harmful or time-wasting websites
• Downloading files from file sharing sites.