Ask HN: Any info on dell scam support calls

Just wondering if anyone knew anything about the scam support calls supposedly coming from Dell. My son just had one and before I caught it he felt it was legit and allowed the person remote access to his laptop. The person had all his details, phone number, name, machine model, service tag etc. So he didn't think about why would Dell be calling out of the blue, we've now had that discussion.

I shut down the network the second I heard the remote session (about 5 minutes into it sadly) and then have scanned every machine and changed all our network creds, router config etc. Nothing shows up on the machines as infected and no rootkits etc were found. Any ideas on what this scam is? Does Dell have a massive security leak or data breach and they aren't discussing it or did I just miss it?

Anything else I should do to try and make sure nothing is compromised? Right now I still have his computers off the network.