Observation

The expected answers were:
(a)(i)    Computer virus is a malicious program which replicates itself and causes damage to the resources in the computer.         

Computer virus is a line/piece of code which is capable of replicating or copying itself and typically has a detrimental/damaging effect on computer files.

A computer virus is a malware that when executed, replicates itself and infects other programs by modifying them.

A computer virus is a program or piece of code that is loaded onto the computer without the user’s knowledge and runs against the user’s intention to cause damage on the computer files.

  (ii) Types of computer viruses
  1.         Trojan horse
  2.         Worms
  3.         Boot sector
  4.         Macro virus
  5.         Memory resident virus
  6.         Rootkit virus
  7.         Polymorphic virus
  8.         Logic bombs / Time bombs
  9.         Multipartite virus
  10.       FAT virus
  11.       Directory virus
  12.       Resident virus
  13.       Direct action virus
  14.       Overwrite virus
  15.       Network virus

(b)         Five sources of computer security breaches
1.         Viruses, worms and Trojan horses, backdoor virus.
2.         Poor implementation of network or bad network administration.
3.         Poor implementation of ICT policies.
4.         User’s negligence or carelessness -giving out of personal and vital information on the web without careful screening.
5.         Hackers, spammers or hacker’s intrusion or breach of computer security.
6.         Deliberate divulgence of company's information.
7.         Downloading of files from untrusted websites.
8.         Eavesdropping
9.         Privilege escalation
10.       Tampering attack
11.       Spoofing attack
12.       Denial of service