Remote access trojans (RATs) are malware that allow hackers to control devices remotely, enabling them to steal passwords, monitor screens, log keystrokes, activate webcams or microphones, install additional malware, and use the computer for further cyber attacks. RATs typically enter systems through phishing, malicious downloads, fake updates, or compromised websites. Signs of a RAT infection include sluggish performance, unusual network activity, mysterious programs, unexpected pop-ups, and unexpected activation of camera or microphone lights. Preventive measures include being cautious with communications, downloading from reputable sources, using antivirus software, keeping software updated, and implementing a firewall. If a RAT is suspected, it is advised to disconnect from the internet, run a full antivirus scan, check installed programs, change passwords, and consider a factory reset. Smartphones can also be vulnerable to RATs, which may manifest as rapid battery drain, overheating, strange pop-ups, excessive data usage, and unfamiliar apps. Immediate actions for compromised phones include enabling airplane mode, deleting suspicious apps, and updating the operating system.