Network Security And Threats

Question 1

What is a firewall?

Answer 1

A security checkpoint designed to prevent unauthorised access between two networks, usually involving an internal trusted and an external network

Question 2

What does a typical firewall consist of?

Answer 2

A separate computer containing two Network Interface Cards (NICs), with one connecting to an internal network, the other to an external network

Question 3

What happens when special firewall software is used?

Answer 3

Each data packets attempts to pass between the two NICs is analysed against preconfigured rules and then accepted or rejected

Question 4

What are the preconfigured rules in a firewall called?

Answer 4

Packet filtering

Question 5

What is packet filtering also called?

Answer 5

Static filtering

Question 6

What does packet filtering do?

Answer 6

Controls network access according to network administrators rules and policies by examine the source and destination IP addresses in packet headers

Question 7

What reasons can static filtering block packets for?

Answer 7

Block packets based on the protocols being used and the port number they are trying to access

Question 8

What is a port?

Answer 8

Is where a client reaches the right computer or network at the right IP address and for example allows the client to download the packets data to a computer

Question 9

What is an example of certain protocols using particular ports?

Answer 9

Telnet, is used to remotely access and uses port 23 so if Telnet is disallowed by a network administrator, any packets attempting to connect through port 23 will be dropped or rejected to deny access

Question 10

What is the difference between a dropped packet and a reject packet?

Answer 10

A dropped party Is removed quietly while a rejected packet will cause a rejection notice to be sent back to the sender

Question 11

What us a proxy server?

Answer 11

Interrupts all packets entering and leaving a network, hiding the true network addresses of the source from the recipient

Question 12

What does using a proxy server do for the user?

Answer 12

Enables privacy and anonymous surfing

Question 13

How can proxy servers help commonly voters websites?

Answer 13

By maintaining a cache of commonly visited websites and return the web page data to the user immediately without the need to reconnect to the Internet and re-request the page from the website server

Question 14

How can proxy servers control over the content that users may demand?

Answer 14

They are often used to filter requests providing administrative controls

Question 15

What is encryption?

Answer 15

Encryption is one way of making messages travelling over the Internet secure

Question 16

What are all types of malware or malicious software?

Answer 16

Worms, Trojans and viruses

Question 17

What do worms and viruses have the ability to do?

Answer 17

Self-replicate by spreading copies of themself

Question 18

What’s the difference between a worm and a virus?

Answer 18

Worms are a sub-class of viruses, but viruses rely on the host files to be opened in order to spread themselves, whereas worms do not

Question 19

What type of virus resident is most common?

Answer 19

memory resident

Question 20

What happens tot eh virus once it is in memory?

Answer 20

Any other uninfected file that runs becomes infected when it is copied into memory

Question 21

Where do other common virus reside?

Answer 21

In macro files usually attached to word processing and spreadsheet data files, that infect data files once created and are usually less harmful

Question 22

How does a worm get into a system?

Answer 22

Resides within a data file and enter the computer through a venerability or tricking the user into opening a file

Question 23

How does a worm replicate?

Answer 23

A worm can replicate itself and send copies to others user from your computer

Question 24

Why can worms be responsible for causing computer or servers to slow?

Answer 24

Worms are often reasonable for using up bandwidth, system memory or network resources

Question 25

What is a trojan?

Answer 25

A type of malware that manifests it self in something useful file, games or utility

Question 26

What are some uses for Trojans?

Answer 26

To harvest personal information, or use your computer power or network bandwidth to send thousands of spam emails

Question 27

What is a difference from viruses, worms and Trojans?

Answer 27

Trojans cannot self-replicate

Question 28

What is the weakest point in security?

Answer 28

Humans

Question 29

What di many malware attacks exploit?

Answer 29

‘buffer overflow’, which occurs where a program accidentally writes values to memory locations too small to handle them, and inadvertent overwrites the value in neighbouring location

Question 30

What is a result of ‘buffer overflow’?

Answer 30

Overflow data is often interpreted as instructions

Question 31

What is another example of social engineering threats?

Answer 31

Phishing (persuading individuals to open files, internet links and emails containing malware)