A RAT (Remote Administration Tool) is a type of virus that allows someone to control another person's computer remotely by stealing personal information like credit cards, gaming accounts, or just for fun. While the programs themselves may not be illegal, infecting another computer without permission is illegal. RATs can steal login credentials, turn on webcams and microphones, and perform other malicious actions on the infected computer. People are often infected by downloading unknown files or programs containing hidden RAT code. The best protection is to avoid downloading untrusted files and monitor your computer for suspicious programs.