Which phase is not included in Virus Life Cycle?

Concept: Virus Life Cycle

A computer virus is malicious code that follows a recognized life cycle. The standard model (as described by Stallings) defines exactly four phases through which most viruses pass during their existence in a host system. Knowing these four named phases lets us identify any label that does not belong.

The four recognized phases

1. Dormant phase — the virus stays inactive after entering the system and waits for a specific condition (a date, the presence of a program, or a disk-capacity threshold) before becoming active. Not every virus has this phase.

2. Propagation phase — the virus places a copy of itself into other programs or into certain system areas on the disk, spreading the infection further.

3. Triggering phase — the virus is activated to perform its function, set off by a defined event such as a count of how many times it has copied itself.

4. Execution phase — the intended function (the payload) is carried out; this may be harmless (a message on screen) or damaging (destroying files).

Contrast: identifying the odd label

Comparing each label against the four-phase model:

• Dormant, Propagation and Execution each name a genuine phase in the model above, so each one belongs to the life cycle.

• “Start” does not appear anywhere in the recognized four-phase model; it is a generic word, not a defined stage of a virus. It is therefore the label that is not part of the virus life cycle.