### Comment:
What is a keylogger and how is it used in malware?

### REPLY:
A keylogger is a powerful tool used in malware to secretly record all keystrokes made on a compromised computer. It can capture sensitive information such as usernames, passwords, and credit card details, which can then be used for malicious purposes like identity theft or financial fraud. Keyloggers can be installed through various means, including email attachments, infected websites, or by exploiting software vulnerabilities.