What Is Malware? Types, Examples and How to Remove It (2026)

Your computer is running slower than usual. Pop-ups appear on websites that don't normally show ads. Your browser's homepage changed on its own. These are classic signs of malware. But what exactly is it — and how do you actually get rid of it?

What Is Malware?

Malware is short for 'malicious software' — any program intentionally designed to damage a system, steal data, or give an attacker unauthorised access. It's the umbrella category. Viruses are just one species inside it.

Malware spreads through email attachments, drive-by downloads, infected USB drives, fake software updates, and compromised websites. The most common entry point in 2026 is still a single careless click on a link in an email.

The 8 Main Types of Malware in 2026

• Virus — attaches itself to legitimate files and spreads when those files are shared or executed.
• Worm — self-replicates across networks without any human action.
• Trojan Horse — disguises itself as legitimate software and runs malicious code in the background.
• Ransomware — encrypts your files and demands payment (usually crypto) for the decryption key. WannaCry and LockBit are infamous examples.
• Spyware — silently collects passwords, keystrokes and browsing data.
• Adware — bombards you with unwanted ads, often bundled inside free software.
• Rootkit — hides deep in the operating system, giving an attacker persistent admin access.
• Keylogger — records every keystroke to steal passwords, card numbers and messages.

Real-World Malware Examples

WannaCry (2017) hit over 200,000 computers across 150 countries in a single weekend, taking down hospitals, telecoms and logistics firms. Emotet was a banking trojan that quietly evolved into one of the most dangerous malware delivery platforms of the late 2010s. Pegasus spyware made headlines for targeting journalists and politicians on iPhones via zero-click exploits.

Warning Signs Your Device May Be Infected

• Sudden slowdown — malware uses CPU and RAM in the background.
• Unexpected pop-up ads, even when no browser is open.
• Browser homepage or default search engine changed without your input.
• Unfamiliar programs in your taskbar, startup list, or system tray.
• Antivirus disabled itself or refuses to update.
• Unusual network activity or a sudden spike in mobile data usage.

How to Check If You Have Malware

Start with the free, built-in tools — Windows Defender's offline scan and Malwarebytes Free are remarkably effective. Then sanity-check anything suspicious you've connected to.

How to Remove Malware (Step by Step)

1. Disconnect from the internet immediately to stop data exfiltration.
2. Boot into Safe Mode (on Windows: Shift + Restart → Troubleshoot → Advanced Options → Startup Settings).
3. Run a full scan with Malwarebytes Free or Windows Defender Offline Scan.
4. Quarantine or delete every detected threat.
5. Remove unfamiliar browser extensions and reset your browser settings.
6. From a separate, clean device, change passwords for your email, bank and main accounts.
7. Re-enable automatic OS and browser updates — most infections exploit unpatched software.

How to Prevent Malware in 2026

• Never open email attachments from unknown senders — and treat 'urgent' invoices with extra scepticism.
• Download software only from official sources or verified app stores.
• Keep your OS, browsers and plugins on automatic updates.
• Use a reputable password manager to limit the damage if any one account is breached.
• Enable two-factor authentication on every important account.
• Avoid logging into sensitive accounts from public Wi-Fi without a VPN.

Frequently Asked Questions

What is the difference between malware and a virus?

A virus is one specific type of malware that attaches itself to files and spreads when those files are shared. Malware is the broader category that also includes ransomware, spyware, trojans, worms, rootkits and more.

Can malware infect an iPhone or Mac?

Yes. While less common than on Windows, both macOS and iOS have seen real-world malware. Macs have been increasingly targeted since 2020 as their market share grew. iOS is more locked down but is not immune, particularly on jailbroken devices.

What is ransomware?

Ransomware is malware that encrypts your files and demands a payment — usually in cryptocurrency — to restore access. It has paralysed hospitals, schools and global supply chains.

Is free antivirus software good enough?

For everyday users, yes. Windows Defender (built into Windows 10/11) and Malwarebytes Free provide strong baseline protection. Paid suites add real-time web filtering, identity monitoring and bundled VPNs on top.

Can malware survive a factory reset?

Most malware does not. However, sophisticated firmware-level rootkits can persist through a reset. For nearly everyone, a full OS reinstall is the most reliable remediation.