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

### REPLY:
A keylogger is a type of malware that captures every keystroke made on a compromised device, including passwords, credit card information, and other sensitive data. This information can then be used by hackers to gain unauthorized access to online accounts, steal personal information, or carry out financial fraud. It's important to note that keyloggers can be installed through various methods like email attachments, infected websites, or malicious software downloads.