What is fileless malware?

Fileless malware is a type of malicious software that doesn’t rely on traditional files to infect a system. Instead of writing code to the hard drive, it operates in memory or uses trusted system tools—like PowerShell or Windows Management Instrumentation (WMI)—to carry out attacks. This makes it harder to detect, since it leaves little to no footprint on the disk and can evade many antivirus programs. Fileless malware often enters through phishing emails or compromised websites and uses legitimate processes to stay under the radar, making it especially dangerous and difficult to remove.