A computer virus is a malware that self-replicates by copying itself to another program. In other words, the computer virus spreads by itself into other executable code or documents.
Attackers create and spread viruses to infect vulnerable systems, gain admin control, carry out phishing attacks and steal user-sensitive data.
The structure of a computer virus includes the following parts:
This mechanism includes how a virus propagates and enables it to replicate. It has two sub-components:
Search: It is used to search for the host program.
Copy: It is used by the virus to copy itself into the executable program.
The event or condition determines when the payload is activated.
It performs the functions for which the virus was designed. It may involve harmful or benign activities.
Note: Anti-detection routines are also a component of a virus. These routines prevent viruses from being detected.
The structure of a computer virus is illustrated in the diagram below:
The life cycle of a computer virus can be divided into four phases:
The virus is idle in the dormant phase. It has accessed the target device but does not take any action.
In the propagation phase, the virus starts propagating by replicating itself. The virus places a copy of itself into other programs or accomplishes certain system areas on the disk. Each infected program will contain a clone of the virus, which will enter its own propagation phase as well.
The triggering phase starts when the dormant virus is activated. It will perform the actions it is supposed to accomplish. This phase can be caused by various system events like the count of the times the virus has cloned or after a set time interval has elapsed.
In the execution phase, the payload will be released. It can harm deleting files, crashing the system, and so on. It can be harmless too and pop some humorous messages on screen.
Computer viruses can harm our systems in different ways. Therefore, it is essential to protect our system by taking safety measures such as keeping a firewall and investing in good antivirus software.
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