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RfidResearchGroup / ChameleonUltra

The new generation chameleon based on NRF52840 makes the performance of card emulation more stable. And gave the chameleon the ability to read, write, and decrypt cards.
https://chameleonultra.com
GNU General Public License v3.0
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Mfc 1k full emulation issue with an OEM terminal #144

Closed spp2000 closed 1 year ago

spp2000 commented 1 year ago

An OEM access control system, in addition to simply controlling access, also allows you to perform a series of operations from the terminal (queries, etc.). To do this, the tag must be left on the reader in order to keep the session open.

Analyzing 3 traces I noticed that, after the first authentication, the system waits for instructions by executing a loop of two READBLOCK: it continuously asks for AUTH-B(12) - READBLOCK(12) - READBLOCK(13) (see pictures).

With Ultra (latest fw) the initial authentication works fine but, during the wait/loops, every 2 seconds (more or less) the communication stops and starts again from the beginning, therefore prevents me from continuing with the next operations.

For the 3 traces acquired we observe that:

I can't acquire more time with pm3, but from the terminal I see that this behavior repeats continuously after about 2 seconds.

Given that this behavior does not seem exactly systematic, I will try to take other traces to have a minimum of statistics on this behavior, if it can be useful. Thank you traceman ;)

Trace n.1

image

Trace n.2

image

Trace n.3

image

mitmarcus commented 1 year ago

can confirm there's still an issue

https://github.com/RfidResearchGroup/ChameleonUltra/assets/114725463/ff0c4722-ba84-4b41-85f7-ac942d792f5f

spp2000 commented 1 year ago

I took more than 10 traces and I can confirm that, in my case, the communication restarts always and only after those commands during the waiting loops. fdt is always about 1600 when the issue occurs, but there is no rule as to when this happens: it can happen after 2, 30, 50, 70, 200 loops indifferently.

spp2000 commented 1 year ago

Ultra Vs Rev.G Rev.G fdt never drops (like Ultra in the pictures above) and are much longer

Ultra

RevG

mitmarcus commented 1 year ago

With 2.0 it seems to work @spp2000 can you check on your readers?

EDIT: works on all readers I have, and even better than previous patches (distance is no longer a problem)

mitmarcus commented 1 year ago

aaaand it's broken again

spp2000 commented 1 year ago

For me nothing has changed since the last time the emulation was improved. The readers that worked continue to work, while the one that was ko remained ko. What problem do you experience?

mitmarcus commented 1 year ago

remember my "problematic" Salto modular XS reader? with the original V2 (2 weeks ago) it was working without issue. I have updated today to the latest and reader won't work again with it.

really no idea what the issue might be.

xianglin1998 commented 1 year ago

@mitmarcus After tracing with SPP2000, we have finally resolved two bugs that affect the simulation of 14a and mf1. You can update to the latest build version to test whether they have solved your problem at the same time. I think this is a high probability.