RfidResearchGroup
MIFARE Classic Anti-Copy Detection
Hello, First of all, thanks a lot for all the great work done here, I learned a lot thanks to this software !
I would find it great if the mifare classic scripts could display a warning if detects a "anti-copy" feature while reading a badge / a dump. The problem and this feature is well described here, seems already implemented for the flipper zero:
https://github.com/flipperdevices/flipperzero-firmware/issues/1345
Does adding this feature seems relevant ? (the main goal would be to prevent users from using copies which would lead to a deactivation of their badge, and to learn about anti copy systems... )
Thanks again.
How a system implements "anti-copy" features is entirely dependent on the system in question, there is no real standard way of implementing such a feature, so there's no real way of implementing such a feature in the proxmark either.
the linked issue shows that they only detect known vigik based system and gives textual warning.
That is quite simple to implement in pm3 client but to add more checks when restore or cload/gload to make sure end user doesn't do something silly is maybe not optimal.
We tend to educate the users instead but I can definitely see why it would be nice to have.
I thought they were talking about anti-cloning features in general and only gave that issue as an example
In either case, I feel like one of the better ways to detect things like this is to warn the user when the reader does a write block command when you try to simulate the dump with the proxmark. In theory this should* be easier to implement since it would basically use the same code as trace list's annotation feature.
Not too sure in practice however.
Identify strange writes to the card when simulating sounds good. When writing to tag too.
But it is like you said, we don't have a generic way to identify those systems. We could gather the knowledge of which system in the discord and maintain a list of them.