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Local Network Captive Portal Chat with OpenWRT (snayss.medium.com)
30 points by snayss 2036 days ago
4 comments

I love fun hacks like this!

Back in college, a group of students and I spent far too much time in some lab space that was on a separate LAN from the rest of the school network (Lab-LAN<->Lab-Router<->Campus-Router<->Internet which meant it bypassed the campus firewall which was nice). One of the regulars wrote a little chat client that abused ARP in some really creative ways to give us effectively an IRC type chat.

Specifically it took advantage the Hardware Address Length field and embedded the message in the Sender Hardware Address field. I can't recall why we didn't just embedded the message in a raw ethernet frame with its dest address set to broadcast... However, there was quite a lot of fun had with what was really a pretty simple hack!

For instance, there was the time we had a stack based buffer overflow which, after some work, one of the gals managed to get RCE with (we had basic stack protection and DEP, but she bypassed it with a ROP chain), which rapidly lead to shenanigans. There was the time some freshmen used it on the normal campus LAN and somehow triggered the shit out of the monitoring IT had in place.

Lots of fun, I'll have to see if I can't dig up the source code for it haha

ahh nice! Bringing hacks like that into the wild is always cool, unpredictable :P I want to mess around more with ARP manipulation....
Does that Medium page send CPU to 80% for you too?

Does that Medium page stall until the browser gives up loading it?

Do you also wish for Medium to die in a fire, so that maybe in the future people will be a tad bit more inclined to write blogs on their own site or less annoying platforms?

I agree. Medium dying in a fire seems like the best option...
hard to transition otherwise :(
You should get a look at PirateBox. It's been recently abandoned, but you could probably get some ideas for chat, image board or forum software for a tiny OpenWrt router.
cool thanks! will check it out
just run an xmpp serveron openwrt instead of python which is not really a good fit
yea I definitely agree that python was not the best choice for this little router haha. Originally I was going to try to write the server in GO but was not able to get compile it for openwrt -- so settled for python . I'm not super familiar with writing xmp servers but looks like it could be a good option, will check it:)
you don't need write xmpp server, the point is that it is ready to use and is small in size, the client is also ready, all you need is to choose one and install it