Fully undetectable

From HandWiki

Fully undetectable (usually shortened as "FUD") can stand for data that had been encrypted, making it appear to be random noise. It can also stand for software that cannot be detected by anti-viruses when a scan is performed.[1] The term is used in hacker circles to refer to something that appears to be clean to many anti-viruses, even though it is a hacking tool.

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