In the context of computer security, which mechanism is primarily used by a computer virus "worm" to duplicate and spread itself across systems and networks?

Introduction / Context:
Computer worms are a type of malicious software that spread automatically from one machine to another, usually over a network. Unlike traditional viruses that attach themselves to host files, worms are often standalone programs that replicate aggressively. This question asks about the mechanism by which worms duplicate themselves, focusing on the idea of creating new running copies of the worm process.

Given Data / Assumptions:

• The question is about a computer virus worm, which is a self replicating program.
• We are asked which mechanism it uses to duplicate itself.
• Options include swap, increment, spawn, and swarm.
• We assume a basic understanding of processes, replication, and network propagation.

Concept / Approach:
In operating system terminology, to spawn a process means to create a new process, often by copying an existing program image and running it as a child process. Worms replicate by making copies of their code on local or remote systems and launching these copies as new processes or services. The term spawn therefore captures the idea of creating new instances. Swap relates to memory management and paging. Increment refers to arithmetic operations on numerical variables, not replication. Swarm is sometimes used informally to describe distributed behaviour but is not the standard term for process creation. Thus spawn is the best match for the mechanism by which a worm duplicates itself.

Step-by-Step Solution:
Step 1: Recall that a worm must create additional running copies of itself in order to spread to other systems or processes.Step 2: Connect this behaviour with the operating system concept of spawning new processes that each execute the same worm code.Step 3: Recognise that swap refers to moving pages of memory between RAM and disk and has nothing to do with replication of code across machines.Step 4: Note that increment is an arithmetic operation and does not describe creating new processes or files.Step 5: Understand that swarm is used metaphorically in some fields but does not specifically mean process creation, making spawn the correct choice.

Verification / Alternative check:
Descriptions of classic worms such as the Morris worm or email based worms explain that the malicious program makes copies of itself on target systems and executes those copies. Technical discussions frequently use terms like spawn or fork to describe how new processes are created in Unix like systems. These words refer directly to the mechanism of starting another instance of a program. Swap, increment, and swarm are not used in this precise sense in operating system documentation, confirming that spawn is the appropriate term here.

Why Other Options Are Wrong:
Swap deals with virtual memory and involves moving data between main memory and disk, not creating new copies of a program across systems. Increment is a simple operation that increases a numerical value, for example in a loop counter, and does not relate to self replication. Swarm may evoke the idea of many entities moving together, but it is a descriptive word rather than a technical mechanism for duplicating processes in an operating system. None of these options correctly describes how a worm creates new instances of itself.

Common Pitfalls:
Some students may be drawn to swarm because they associate worms with large numbers and spreading behaviour, but the question is about the specific mechanism of duplication, which is process creation. Others may not be comfortable with operating system terminology and overlook spawn. To prepare for computer security questions, it helps to link the idea of a worm with both network propagation and process spawning on each infected machine.

Final Answer:
The correct answer is Spawn, because a worm duplicates itself by spawning new running copies of its code on local or remote systems.