A university's examination management system has been compromised by a virus…
A university's examination management system has been compromised by a virus attack originating from infected USB drives and downloaded files. The system administrator must investigate and explain the virus behaviour.
(a) How does a Virus spread through a computer system? What infected media are commonly responsible?
(b) The antivirus software fails to detect the virus as it keeps changing its code. Identify this virus type and explain its behaviour.
(c) Some viruses target the university's Word and Excel documents rather than executable files. Which virus type is this? How does it operate?
(d) Differentiate between File Infector Virus, Rootkit Virus, and Boot Sector Virus in tabular form.
Attempted by 1 students.
Show answer & explanation
(a) Virus
Viruses are self-replicating programs that attach themselves to other programs or files on host computers. They spread through infected media such as:
Songs and video files downloaded from untrusted sources
Software downloads from unofficial websites
Infected USB drives or external storage media
They activate only when a user opens the infected program, making early detection difficult.
(b) Polymorphic Virus
This is a Polymorphic Virus — it continuously changes its own code each time it replicates to avoid detection by antivirus software. Despite changing form, it retains its malicious function. This makes it one of the most difficult virus types to detect and remove, as signature-based antivirus tools cannot recognize its ever-changing pattern.
(c) Macro Virus
This is a Macro Virus — it targets document files such as Word and Excel that contain macros. Unlike traditional viruses that infect executable files, macro viruses embed themselves within document macros and activate whenever the document is opened. They spread easily through email attachments and shared documents.
(d) Virus Types — Comparison Table
Virus Type | Target | Working |
File Infector | Executable files (.exe, .com) | Attaches to program files; activates on execution |
Rootkit Virus | System core/OS level | Hides deep in system; gives attacker root-level control |
Boot Sector Virus | System boot area | Infects master boot record; activates before OS loads |