Malicious websites are online pages designed to harm users or their devices. They may contain harmful software, known as malware, which can steal personal information or damage files. These sites often disguise themselves as legitimate to trick users into visiting them. Users can encounter malicious websites through deceptive links in emails, social media, or search results. It's important to be cautious and use security measures, such as antivirus software and web filters, to protect against these threats. Staying informed about online safety can help prevent falling victim to these harmful sites.