What are computer viruses?
A computer virus is a type of Malware (malicious software) that propagates by copying itself into other programs or files. A virus can damage files, systems or networks — often without the user noticing immediately.
The name comes from biological viruses, which also spread and cause damage within a ‘host’.
🧠 How does a virus work?
- 📥 Infection: The virus reaches a system through infected files, USB sticks, email attachments or downloads.
- 🦠 Activation: The virus becomes active when the infected file is opened or executed.
- 🔁 Propagation: The virus spreads to other files, systems or networks.
- 💥 Damage: The virus may corrupt files, delete data, slow down systems or grant access to attackers.
🧪 What can viruses do?
- Corrupt or delete files
- Slow down or disrupt processes
- Open access points for other Malware
- Steal user data or passwords
- Attempt to spread to network devices, including OT components such as PLCs or SCADA systems
🔄 Difference from other malware
| Type of Malware | Characteristic |
|---|---|
| Virus | Spreads via files and programs |
| Worm | Spreads independently across networks |
| Trojan | Disguises itself as legitimate software |
| Ransomware | Encrypts files for ransom |
| Spyware | Covertly gathers information about the user |
🛡️ How do you protect against viruses?
- Use up-to-date antivirus software
- Do not open suspicious emails or attachments
- Only run trusted software
- Restrict external media (such as USB drives) on critical systems
- Apply network segmentation between IT and OT systems (as in the zones and conduits model)
- Keep operating systems and applications up to date
📌 In summary
A virus is a self-propagating form of Malware that can damage files, systems or networks. Sound security measures and awareness are essential to prevent infection and propagation — especially in environments where continuity is crucial, such as industrial automation.