A computer virus is a hidden, self-replicating section of software, usually with malicious intent, that spreads by infecting other programs, i.e., by inserting a copy of itself and becoming part of another program. A virus cannot function independently; it requires the host program to be executed in order to activate.

Main Characteristics

1. Self-replication: A virus is capable of creating copies of itself. This is one of the most dangerous aspects, as it allows the virus to spread rapidly through computer systems.
2. Infection: A virus infects other programs by inserting its own code into them. When the infected program is executed, the virus is activated and begins its propagation process.
3. Host Dependency: A virus cannot execute its own code independently. It must be launched along with the infected program to perform its malicious function.
4. Potential Damage: Viruses can cause a wide range of damage, from simple annoyances like displaying unwanted messages to deleting important data or damaging the operating system.

Modes of Infection

• File Infector: These viruses attach themselves to executable files (.exe, .com) and spread every time the infected file is executed.
• Boot Sector Virus: They infect the boot sector of a hard drive or storage device, activating when the system starts up.
• Macro Virus: These viruses infect document files, such as those created with Microsoft Word or Excel, by using macros.
• Script Virus: They infect script files, such as those written in scripting languages like JavaScript or VBScript.

Prevention and Removal

To protect your system from viruses, it is essential to adopt a series of cybersecurity best practices:

1. Antivirus: Use updated antivirus software that can detect and remove viruses.
2. Software Updates: Keep your operating system and programs updated to avoid vulnerabilities that can be exploited by viruses.
3. Regular Backups: Perform regular data backups to ensure they can be restored in case of infection.
4. Caution with Attachments: Avoid opening suspicious email attachments or those from unknown senders.

Knowing about computer viruses and understanding how they work is essential for adopting effective protection measures and keeping your data and systems secure.