How can wired traffic be intercepted if the switch decides where to send the packet?

Question

Computer networks

I'm trying to figure out why SSL is needed. Each computer is connected to the switch by a separate wire. The switch determines where to send the packet based on the MAC address. How is traffic intercepted at the network level?

Answer 1

Well, let's think ...
1) at the physical level, you can insert a tie-in into the cable, somewhere on the last mile there may be a radio relay span (you won't even know about it), here you don't even need to insert, in the end you can also go to the transit get physical access to network equipment, and there are also tools for analyzing the electromagnetic background (even through power cords)
2) at the data link level, you can use arp spoofing, overflow the switch switching table, catch the xSTP config curve, experimentally select a poppy / vlan on a neighboring port for artificial collisions ...
3) at the network level, you can replace the gateway (many different techniques and using the same ARP, VRRP, stupid IP address spoofing), DHCP, tweak routing protocols (oh, there's a whole field for maneuvering) and let transit through itself.
4) at the application level, phishing, DNS hacks have already become the talk of the town, so there the applications themselves break perfectly.
And somewhere else there is MPLS, traffic mirroring (the so-called lawful interception), servers for working with all this stuff ...

Answer 2

You are confusing levels .
SSL encrypts traffic on your computer, and it is only decrypted on the server. In theory, no one can read your data, even if they control the wires. Although it will be visible where the packets go, but what is in them is not known.
MAC addresses are relevant only on the local network, that is, up to the first router. And then no one will catch your MAC on the Internet.
It's on the fingers. :)

Answer 3

you don’t have to worry, but agree that since everyone uses it, it’s safe,
and as soon as you mature, if necessary, then implement MITM, and vvedite123 and other certificate substitutions

Answer 4

Cut the cable between the computer and the switch, plug both ends into the hub, plug in a laptop with wireshark at the third end, and start listening.

Answer 5

It's easy to intercept traffic
1. Embed a stupid hub. And then, as in a fairy tale, tcpdump t all all all ... :)
2. Enable mirroring on the smart switch and listen to traffic.
3. A bunch of other more cunning and highly specialized methods .... well, there are a lot of them that cannot be described, since the signal transmission methods are very diverse ....
4. Yes, and SSL will not help from everything, a banal virus on your computer can already catch decrypted data.