No, signatures have nothing to do with this. The ml models embedded in those products (and what is evaluated on Virustotal) can flag legit software that has had a RAT executable inserted in it by modifying the binary. The ml models are trained on thousands of features, and are pretty good at classifying malware. USCYBERCOM has been tweeting APT malware that was not seen by these models or anyone in the public, and yet was still flagged.
https://twitter.com/CNMF_VirusAlert . That would be completely impossible if these products were relying on signatures. Regardless, the entire point I was making in my original comment is that this article is far from clickbait nonsense, because you have a chance, significant from what I've seen, of flagging something like the backdoored pieces of software I linked or never before seen malware like in the tweets above because the malware exists as compiled code. JavaScript is currently not evaluated whatsoever by ANY software security product, so the chances of it being flagged and blocked is 0. Signatures and polymorphism are 10 years ago quite frankly. Backdoored Slack exfilling data in steganographic images over https to giphy.com and instagram and twitter and shit is one future realm of malware. Both the binary and the network traffic are completely indistinguishable from legitimate usage.