A keylogger is a type of malware that records the keystrokes of a user and sends them to a remote attacker1.
The attacker can use the captured information to steal passwords, credit card numbers, or other sensitive data. A keylogger can be installed on a computer by attaching a small USB drive that contains a malicious executable file, such as grabber.exe2. The output.txt file may contain the recorded keystrokes. The user should remove the USB drive and scan the computer for malware.
References: 2: What is grabber.exe? (https://www.freefixer.com/library/file/grabber.exe-55857/) 1: What is a keylogger? (https://www.kaspersky.com/resource-center/definitions/keylogger)