Virus
A computer virus is a type of malicious software that attaches itself to files or programs and spreads from one device to another. Its main goal is to damage systems, disrupt normal operation, or gain unauthorized access.
How it works
A virus activates when an infected file or program is opened. After that, it can copy itself and spread to other files or devices. Unlike some other threats, a virus usually needs user action to start working.
What a virus can do
Depending on its design, a virus may:
- corrupt or delete files
- slow down system performance
- cause system crashes
- open security holes for attackers
Some viruses remain inactive for a while and trigger only under specific conditions.
How viruses spread
Common ways viruses spread include:
- infected email attachments
- downloaded files from unsafe websites
- USB drives and external storage
- pirated or cracked software
Once one device is infected, the virus can spread further.
How to stay protected
To reduce the risk of viruses:
- use reliable antivirus software
- keep your system and apps updated
- avoid opening unknown files or links
- scan external drives before using them
Good digital hygiene is the best defense.
Simple example
Opening an infected file is like letting a stranger into your house who then unlocks all the doors for others. That is how a virus spreads inside a system.
Related terms
- What is Trojan?
- What is Worm?
- What is Antivirus?
Source
Information simplified from the Wikipedia article “Computer virus”.