cups-browsed <= 2.0.1 binds on UDP INADDR_ANY:631 trusting any packet from any source
Well that would explain why I didn’t have it installed (although I did have other parts of cups until jwz coincidentally reminded us two days ago that it can all be removed if you don’t have a printer.) I clear out anything that opens ports I don’t need to be open. A practice I would recommend to anyone.
I mean I guess that’s sound advice if you don’t need to, I don’t know, print?
Entirely personal recommendation, take it or leave it: I’ve seen and attacked enough of this codebase to remove any CUPS service, binary and library from any of my systems and never again use a UNIX system to print. I’m also removing every zeroconf / avahi / bonjour listener. You might consider doing the same.
Great advice. It would appear these developers don’t take security seriously.
Mdns is something most people have no idea exists.
Oh, neat, all my devices broadcast all their open ports, services, addresses, hardware and names? Cool!
No.
If your router/firewall is configured to let these broadcasts through you have a problem. If it is working correctly and you have an attacker on your lan? You have already lost.
It depends. If you’re using a laptop and say you take it to university or work then you’re not on your LAN. You’re on someone else’s LAN and they may have no interest in trying to stop these types of attacks via any kind of client isolation or it may be incomplete.
I can imagine it’s a very normal scenario for university students to have CUPS running and available on all networks as they may need to print at their university.
They’re standardised zeroconnf protocols. Apple was part of the early development.
Bonjour is the apple implementation for mDNS.
Avahi is the GPL compliant implementation.
mDNS, llmnr (ms developed), have been known for ages to be vulnerable.
https://en.m.wikipedia.org/wiki/Zero-configuration_networking#Standardization
*I don’t like apple
damn. that’s a pretty shit one.
BRB.
sudo apt purge cups
Done. This should not even be part of baseline Ubuntu desktop. Speaking for myself but I have not had a printer for about 15 years. The paperless office really did become reality.
About 25 years for me.
For most people it’s a better option to use a local print shop for the odd times that they need something printed.
More options for printing too.
I don’t know if I would like to have my personal data that I needed to print out on any system in a print shop. Printers and Copy machines in print shops often have internal HDD where the files are stored for caching reasons, often for months or even years (depending of the size of the HDD and how much the device is used) until some internal cleanup process deletes them.
Udp sent to port 631. Isn’t firewall on router going to block that anyway?
Right so whats the issue here? If I have cups exposed to the internet I deserve to get ruined. LOL
