In cybersecurity, RAT stands for Remote Access Trojan. It is a type of malicious software (malware) that allows a remote attacker to control a system as if they have physical access to it. RATs are designed to stealthily infiltrate a computer or network and grant unauthorized access to the attacker. Once installed, a RAT enables the attacker to perform various actions on the compromised system, such as:

1. Monitoring: Observing user activities, capturing keystrokes, recording screen activity, and accessing files and documents.
2. Manipulation: Modifying or deleting files, installing additional malware, or altering system configurations.
3. Surveillance: Activating webcams or microphones to eavesdrop on conversations or capture audio/video footage.
4. Control: Executing commands remotely, controlling system shutdown or restart, or downloading/uploading files.

RATs are typically spread through phishing emails, malicious websites, or by exploiting vulnerabilities in software. They pose significant risks to individuals and organizations by compromising data confidentiality, integrity, and availability. Detecting and removing RATs often requires advanced cybersecurity tools and expertise to mitigate the potential damage caused by unauthorized remote access.