If they had a single certificate and used that across devices then the private key could be compromised and used to authenticate malware or pull off a man in the middle attack on an HTTPS site since your system now trusts this new CA. By generating the private key locally and throwing it away, you can be relatively confident that no one has the private key to this new root CA.
What's silly in the first place is that something not trusted to install unsigned drivers still has the perms to install a new root CA but given that constraint, this is a better solution than what Savitech did.
I can't see how buying an actual cert could be more risky than installing a new root CA. The goal of signing is to ensure origin and anti-tampering: two fails in this case. So now you may have a tampered with driver that doesn't remove the private key and uses the new CA to inspect your TLS traffic, and you wouldn't know.
I don't. Not even Microsoft themselves. There were embarrassing slips.
If they had an actual root CA with a private key, they'd sign it locally (on the company machine). In no scenario would the company's private key be given to a customer (unless we're talking about Adobe).
But what do you want to do more?
1) Trust some company to keep a very important private key secure for a long time? (with attackers knowing it's a single high-value target)
2) Or be confident that the private key was used once and destroyed forever? Even if the private key generated on your device could be recovered it would only be good for an attack against you making it a lower priority to attackers.
Doing it that way completely undermines the reason for having a cert in the first place. You might as well not have one at all.
I'd still prefer the latter, given reasonable standards in terms of key handling, but the one-time trust is not completely without merit. It would certainly be more reasonable though to just allow one-time blind trust without forcing the installer to create a certificate that may or may not be as private as advertised.
Alternatively they would need to ship hundreds of different drivers or a single driver that binds to hundreds of different device IDS. Not nice.
And now this developer is learning on HN he should remove that line in his resumé.
Or maybe he thought it was a clever idea... Let's call it a learning experience.