Malware — short for malicious software — is any program or file designed to harm a computer, steal data, spy on users, or cause disruption. It’s one of the oldest and most persistent cybersecurity threats.
Understanding the types of malware, how they spread, and how to stop them is essential to keeping your devices — and your data — safe.
Why It Matters?
Malware can:
- Steal your login credentials and credit card numbers
- Lock you out of your files or system (ransomware)
- Turn your device into part of a botnet used for cyberattacks
- Spy on your activity without your knowledge
Even if you have antivirus software, knowing what you’re up against helps you avoid risky behaviour and respond quickly to infections.
Common Types of Malware (and What They Do)
🧬 Viruses
- Attach to legitimate files and spread when opened
- Can corrupt or delete data, crash systems, or steal information
🐎 Trojans
- Disguised as legitimate software (e.g., fake updates or cracked apps)
- Create backdoors for attackers to control your device
🛑 Ransomware
- Encrypts your files and demands payment for their release
- Often delivered through phishing emails or malicious attachments
🔗 Learn more: Ransomware Guidance – NCSC
🕵️ Spyware
- Monitors your activity, collects keystrokes, tracks browsing habits
- Often runs silently in the background
🐛 Worms
- Self-replicating malware that spreads across networks
- Unlike viruses, don’t need user action to spread
🧟 Botnets
Used for DDoS attacks, spam, crypto mining
Infected devices that act as a “zombie army” under hacker control
How Malware Spreads
Infected ads (malvertising)
Email attachments and phishing links
Downloading software from untrusted sources
Visiting compromised websites (drive-by downloads)
USB drives and other physical media
How to Protect Yourself
✅ Use Trusted Antivirus and Anti-Malware Software
- Free and paid tools offer real-time protection and scheduled scans
🛡️ Keep Software and Systems Updated
- Security patches fix vulnerabilities used by malware
🔗 Don’t Click Suspicious Links or Open Unknown Attachments
- Especially in emails, DMs, or pop-ups
🔒 Enable a Firewall
- Blocks unauthorised incoming and outgoing connections
👁️ Use Browser Extensions to Block Trackers and Ads
Tools like uBlock Origin and NoScript
What to Do If You’re Infected
Disconnect from the internet to prevent spread
Run a full malware scan using a reputable tool
Remove the malware (use safe mode or bootable antivirus if necessary)
Change your passwords on all accounts
Restore from backup if necessary
Report the incident if it affects work, clients, or sensitive data
Free Tools to Scan and Remove Malware
Further Reading and Resources