### Comment:
How can malware be hidden within legitimate files?

### REPLY:
Malware can be hidden within legitimate files through techniques such as file extension manipulation, file compression, or encryption. By changing the file extension to something commonly trusted, like .doc or .pdf, attackers can deceive users into opening the file. Additionally, malware can be compressed or encrypted using tools such as WinRAR or AES encryption, making it harder for antivirus software to detect.