Re:Chrome’s address bar will use https:// by default
by grahamburger on Tuesday March 23, 2021 @10:14PM
(#26562788)
One problem is that it's easy to inject malicious DHCP on to any network you have access to, and you can then route all traffic to yourself (by telling clients that you are the gateway.) This kind of attack is partially mitigated because of TLS - redirecting all traffic to yourself isn't particularly useful if it's all encrypted. But if you could issue a cert along with the DHCP it'd be game over for everyone on the network.
Re:Chrome’s address bar will use https:// by default
by midasuni on Wednesday March 24, 2021 @02:16AM
(#26564115)
If you’re the network operator you can mitm network traffic if curse. If you aren’t how are you running a dhcp server when the switch will block the packets?
Re:Chrome’s address bar will use https:// by default
by grahamburger on Wednesday March 24, 2021 @02:46AM
(#26564229)
Switches don't typically block DHCP packets. You can literally just spin up your own DHCP server and plug it in to a switch port - if your fake server responds to a DHCP request faster than the legit DHCP server the client will get your lease instead of the right one. It's this way by design - it's not at all uncommon for the DHCP server to not run on the router itself, but on some other device elsewhere in the network, or even outside the layer 2 network using a DHCP Relay.
E.g. your router/DHCP controller/AD box gives an IoT device a DHCP ip and maybe a DNS address, and additionally it will provision a cert+key to that device by some standard protocol (keeping this secure might be impossible?). Router has an internal CA cert+key to do this.
Your PC then (handwavy) "knows" to retrieve the CA cert of your router by some standard protocol (dhcp extension?), and "knows" to trust it for devices on the router's subnet.
Is a scheme like this possible?