Keylogger

A keylogger captures every key pressed on a keyboard and saves or transmits the log to an attacker. Because everything you type — passwords, credit card numbers, private messages, search queries — passes through a keylogger, it is one of the most effective tools for credential and identity theft.

Software keyloggers are delivered as malware and run invisibly in the background. Hardware keyloggers are small physical devices plugged between the keyboard and computer — these are used in targeted attacks and have appeared on shared computers in public settings.

Keyloggers are often packaged with other malware as part of a larger payload — a remote access trojan (RAT) might include keylogging among its surveillance capabilities. Anti-keylogging measures include up-to-date security software, using virtual keyboards for sensitive inputs, and keeping operating systems patched.