Fileless malware Fileless malware never writes itself to disk during the attack, so antivirus software has a harder time finding it. While it operates it lives in memory and works with tools the system already has — PowerShell, scripts, built-in commands. Because it delivers its payload through legitimate tools, its activity is not easy to tell apart from normal work.

Loader / Dropper Loaders and droppers are couriers. Their only job is to deliver the infection to the machine. A dropper carries the payload with it and writes it to the system; a loader is usually smaller and pulls the payload from the internet only once it has landed. Neither does anything more than that — and that is their advantage.

Password spraying Password spraying is brute force turned around. Instead of trying many passwords on one account, the attacker tries common passwords across many accounts. That avoids lockout, because each individual account sees only an attempt or two.

Zero-Day Exploitation Zero-day exploitation uses a vulnerability for which the vendor has no patch yet, or does not know exists. The name says how much time the defense had to prepare: zero days. In practice a victim can be doing everything right, keeping systems and applications up to date, and still be exposed.