Placebo Antivirus

Also called Placebo Antimalware.

An antivirus program that "detects" fake malware to make it seem like it works.

Origin: A placebo is something that you are told works and seems to be working but actually doesn't do anything.

Most, if not all, antivirus programs were placebo antivirus programs until there was a surge in viruses made by people who decompiled their code.