Malware and device infection - from ransomware to the USB Killer

Malware reaches a device not by magic but through predictable doors: an email attachment, pirated software, a fake app, someone else’s flash drive. Let’s go through the main threats and - most importantly - where the line of defence actually runs, because an antivirus does not hold it on its own.

Ransomware

You turn on the computer and see: “Your files have been encrypted. Pay the ransom - or lose everything.” Ransomware gets in through a phishing email, an infected file or a system vulnerability, encrypts your documents, photos and videos, and demands money (usually cryptocurrency) for the key. Even after payment there is no guarantee you will get your files back - so paying is not worth it: it does not restore the data and it funds criminals.

The only reliable protection is backups. Keep them on media disconnected from the main network (an external drive that is not permanently plugged in): ransomware encrypts everything it can reach, including connected network drives.

Spyware and keyloggers

A keylogger records every keystroke - including passwords and card numbers. Spyware takes screenshots and turns on the camera and microphone without your knowledge. Such programs hide inside free or pirated software, run silently in the background, and transmit your data to attackers for months.

Protection:

• avoid pirated software - the most common infection route;
• watch for unusual behaviour: sudden slowness, overheating, excessive traffic;
• cover the camera or use the shutter when you are not filming;
• a password manager instead of manual typing makes life harder for keyloggers.

Fake apps

You install a “free photo editor” - and get spyware with it. Fake apps disguise themselves as real ones and even make it into official stores. They steal passwords, read SMS, track location or mine cryptocurrency in the background; sometimes they copy a bank’s interface to phish your login.

• install apps only from official stores;
• check the developer and reviews - few downloads and a fresh developer account are a red flag;
• read the permissions: why does a flashlight need your contacts?
• don’t install APKs from unknown sources (Android);
• periodically review the app list and remove what you don’t need.

Infected USB - and a physical weapon

A flash drive found in a car park or gifted by a stranger must not be plugged in: attackers deliberately “drop” infected media. Malware can start automatically (autorun) or hide behind an ordinary-looking file.

But there is worse - the USB Killer. An ordinary-looking flash drive that, on connection, physically burns out the device. The mechanism: it takes the standard 5 V from the port, a high-voltage converter accumulates charge in capacitors and raises the voltage to about 200 V, then discharges that pulse back into the USB data lines. The process repeats many times a second - and usually causes irreversible damage to the motherboard, the USB controller, sometimes the CPU. Makers position it as a “port tester for surge resistance”; using it against someone else’s property is a criminal offence.

The defence is simple and the same: never plug in unknown USB devices, regardless of where you found them. Additionally - disable autorun, scan removable media, and buy flash drives only from trusted sellers.

The truth about antivirus software

There is no “best” antivirus - that is a marketing myth. Effectiveness depends on the OS, your habits, the device type and even the region (which threats are common where). Built-in solutions (Windows Defender, Apple XProtect) are often underrated, yet they hold basic protection perfectly well.

What actually matters:

• keep the antivirus updated - threat databases update daily;
• don’t run several antiviruses at once - they conflict and slow the system;
• cross-check independent tests: AV-TEST and AV-Comparatives;
• on smartphones the best protection is an updated OS + common sense; most “mobile antiviruses” are marketing.

The key point: an antivirus is not armour, it is one layer. No antivirus will stop you from clicking a phishing link if you decide to. The human factor remains the biggest vulnerability.

Takeaways

• Ransomware is cured not by paying but by offline backups.
• Spyware and fake apps arrive with pirated software and excessive permissions - read what you install.
• An unknown flash drive is either infection or physical destruction. Don’t plug it in.
• An antivirus is one layer among many; the main vulnerability is the human, not the absence of the “best” program.