Chapter – 5 | What are Computer Viruses?

this type of malwares are responsible for cyber attacks, but how? in this post we will understand this, if you are confused as to why you are here check out my The complete ethical hacking course | 2020.

Let’s Understand.

The word Virus is a acronym, it stands for

Vital Information Resource Under Siege

Virus is a piece of code which once executed, starts performing tasks in the background.

Effect of Virus attack in System : –

A victim may not understand its existence right at the beginning, but as time progresses, various symptoms of virus infection can be seen, these symptoms vary as the code variation occurs.

Symptoms of Virus : –

Some virus will use up all the computing power, due to this victim’s machine performs very slow as majority of its resources are being used by the virus.


A virus damage increases as it spreads to other disks and drives.

However, it always needs to attach itself to a host file or an application to spread.

Say, you downloaded a .srt subtitle file and along with this there is a fishy .bat file as well.

Victim then might copy that file without paying much attention and even gave the copy to another person.

Even the victims deletes the file from root directory, the file already has replicated itself.

Through main disks and USB devices the virus can infect multiple systems just like that.

Components of Virus :

There are three major components of Virus.

  1. Concealer
  2. Payload
  3. Replicators

1. Concealer

During the creation of Virus the Hackers created it’s appearece such that it appears genuine benign application.

Camaflauging the icon as some other application’s icon is one way of doing it.

This way the victim is fooled to think that the file is trustworthy.

2. Payload

Payload is the actual piece of code where the instructions are stored.

This decides the behavior of Virus.

3. Replicator

How the virus is spread is handled by this component.

It can be applied to internet and different networks as well.


Different Phases of Virus : –

Let us look at the life cycle of a virus in a system.

  1. Dormant
  2. Propogation
  3. Triggering
  4. Execution

1. Dormant : –

In this state the virus is not active, it is just dormant in user’s system.

In this phase it just exist within a system.

Not all viruses will have this phase.

2. Propogation : –

While still being in dormant state, the virus can propagate itself to other files and programs.

So that the virus can propagate itself to affect different systems.

3. Triggering : –

Now that the Virus has propagated itself in multiple systems.

But it is still dormant as no execution has happened.

Triggering phase becomes the starting point of execution of the virus.

Normally, triggering are kept at a certain date/time.

Once the system date and the scheduled Virus execution date matches, mayhem happens.

4. Execution : –

This phase is where the payload of the Virus is executed.

Each virus will behave differently according to their code in payload.

This is where the users will start noticing the damage to their systems.


Thank you for reading

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