by Sethioz » Wed Nov 02, 2016 6:33 pm
everything is possible, you just gotta do research and see how it works.
I haven't done any research on VAC, but most likely it simply bans your game serial, so when you try to join a server with that serial, you get kicked.
from what i know, you can use packed editors to make server think you are not banned. For example in some older games, when server sent you a message "you're banned", but you modified your game client to ignore that message, then server still accepted the packets after that, still allowing you to join.
It's a lot of work and i don't think anyone would do this just for the fun of it and if they do, they wouldn't release it in public cuz it would get patched very fast.
VAC ban is same as any other ban, so i'm quite sure it bans your serial and that's it.
There are many ways to try and bypass any type of ban, but you need to know how to debug the game and its protocol and find out how the system works and then try to manipulate it. For example in some games you can steal somebody's "session id", like stealing cookies on websites and then use that, so you join as someone else, while still playing from your own account.
If game has specific check towards the serial, then i don't think you can unban yourself. For example like Wireless WPA2 authentication works with 4-way handshake, where you router sends you decrypted data and your client encrypts it with the key you provide, then you send the encrypted data back and router compares that data to the data it encrypted itself with the right key, so if they match, then router communicates with the client, however router always sends the encrypted files after that, so even if you make router think that you had right key (which doesn't happen), then you still get encrypted data which you can't decrypt. so check is done on the router side.
Same method is used in some games and websites, where check is made on server side and there's nothing you can do about it.