- To exploit this across the internet or LAN, a miscreant needs to reach your CUPS service on UDP port 631. Hopefully none of you have that facing the public internet. The miscreant also has to wait for you to start a print job.
- If port 631 isn’t directly reachable, an attacker may be able to spoof zeroconf, mDNS, or DNS-SD advertisements to achieve exploitation on a LAN. Details of that path will be disclosed later, we’re promised.
So don’t expose 631 to the internet (why would you?) and know who’s on your network. Be careful printing things on an untrusted network.
It’s serious, but seems like a wonky attack vector for most.
It’s serious, but seems like a wonky attack vector for most.
Yeah, it’s super trivially exploited, BUT it requires you to do a series of dumb things or let an attacker have access to your LAN which is one of those you-have-bigger-problems moments anyways.
And then you have to use their added printer (though there’s an exploit path that may be usable to over-write the printer you already have configured, if the attacker knows what that might be) to print something before anything happens.
Dude who found it seems to have overhyped it just a little bit (while being a huge dick about it), but I could see how you might exploit this in certain circumstances.
This could be an issue on like a college campus or something. Under those circumstances one should definitely be running a host-based firewall though.
Yeah, and at that point your network should be enforcing client isolation too, which is also a mitigation for this specific issue in large, shared networks like a college campus, or office, or public Wi-Fi at wherever.
And to add to that most of the time CUPS is only exposed to local host by default.
If you have CUPS exposed to the public Internet you have much bigger problems than a new CUPS vulnerability. For all of the hype this exploit received over the last week it’s the biggest nothing burger I’ve seen all year.
