The playbook

Crypt / FUD

Crypting is the service of repacking malware until antivirus engines stop recognizing it. FUD, "fully undetectable", is the advertised result, sold with a guarantee and re-crypts included.

Why it matters to you

A signature is a snapshot of one crypt. This is why detection engineering favors behavior over hashes: the hash changes nightly by design.

Where we meet it

Crypting services advertise their detection rates like a benchmark, and re-crypt on a schedule. Watching the service is more durable than chasing the hashes it produces.