It seems like nothing else could go wrong with this computer. If this was a game of malware bingo, you would be one step away from winning the jackpot. For fun, you investigate some command-line programs to see if they’ve been altered. Aaaand, did someone say bingo?

Fileless malware is a type of malware that ‘lives off the land’ and uses legitimate tools and the user’s operating system to perform malicious activities like privilege escalation, data collection, and more. It’s incredibly hard to detect and almost always missed by antivirus software.

Unlike a Trojan Horse, fileless malware is not pretending to be legitimate software, it actually is a part of legitimate software. Fileless malware hides itself within the code of legitimate software, often altering existing code to make it malicious.

Certain programs, like Microsoft PowerShell, are particularly vulnerable to these attacks. Someone could use this attack vector to gather data, use your device resources to mine cryptocurrency, or even install other malware.