Malware attacks can crack weak passwords, bore deep into systems, spread through networks, and disrupt the daily operations of an organization or business. Other types of malware can lock up important files, spam you with ads, slow down your computer, or redirect you to malicious websites.

Trojans. A Trojan (or Trojan Horse) disguises itself as legitimate software to trick you into executing malicious software on your computer. Because it looks trustworthy, users download it, inadvertently allowing malware onto their device.

Malware, short for malicious software, refers to any intrusive software developed by cybercriminals (often called hackers) to steal data and damage or destroy computers and computer systems. Examples of common malware include viruses, worms, Trojan viruses, spyware, adware, and ransomware.

Malware can use known software vulnerabilities to infect your PC. A vulnerability is like a hole in your software that can give malware access to your PC. When you go to a website, it can try to use vulnerabilities in your web browser to infect your PC with malware.