Malware explained

Malware is software designed to harm your device or steal from you. It arrives through downloads, infected websites, or phishing. Here is what the main types do and how to protect yourself.

Viruses and worms

Viruses attach to files and spread when those files are opened or shared. Worms spread on their own over the network, often by exploiting unpatched software. Both can corrupt data, steal information, or create backdoors for attackers. The Conficker worm in the late 2000s infected millions of Windows machines; many infections today still exploit known vulnerabilities that patches would have fixed.

Keep your operating system and applications updated. Enable automatic updates where possible. On networks, segmentation can limit how far malware spreads—if one machine is infected, it cannot easily reach others.

Trojans

Trojans pretend to be legitimate software. You download what you think is a game crack, a "free" PDF converter, or a fake Windows update—and you run it. The malware installs in the background. Trojans often open backdoors, steal passwords, or install ransomware. Pirated software and "codec packs" are common carriers.

Only download from official sources or trusted distributors. If you need free software, get it from the developer's site, not a random download portal. Check that the publisher name matches what you expect. When your browser or OS warns about an unsigned or unknown publisher, take that seriously.

Ransomware

Ransomware encrypts your files and demands payment to unlock them. Some variants also steal data and threaten to publish it. It often arrives via phishing links or trojanized downloads. Once it runs, it can encrypt local drives and any connected or mapped network shares.

Backups are the main defense. Keep at least one backup that ransomware cannot reach— offline, or in a system with different credentials. Test that you can restore from it. Paying the ransom does not guarantee you get your data back, and it funds further attacks. Prevention—patching, blocking macros, avoiding suspicious downloads—matters more than hoping to negotiate later.

Spyware and stalkerware

Spyware monitors what you do: keystrokes, screenshots, location, messages. Stalkerware is spyware used in abusive relationships—a partner installs it to track the victim. It can be hidden in "family tracker" or "parental control" apps, or installed physically on a shared device.

If you suspect stalkerware, removal can alert the abuser. Contact a domestic violence organization or tech-safety project for guidance—they understand the safety implications. For general spyware, run a reputable antivirus scan and review installed apps for anything you do not recognize.

What encryption and anonymity do not fix

Full-disk encryption protects your data if someone steals your laptop—they cannot read it without the key. It does not stop malware that runs while you are logged in. Anonymity tools like Tor hide your network traffic; they do not sanitize files you download or run. Malware can still infect you and phone home. Use encryption and anonymity where they help, but do not assume they replace safe browsing and download habits.