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#1 2020-06-22 04:02:00

Registered: 2020-06-19
Posts: 2

Odd iClass quirk with Proxmark3: Anyone experienced before?

Hi, I noticed that recent iClass cards/fobs I purchased had an odd behaviour. They were presumably manufactured before HID 'upgraded' the chips to one that can't be read by our pm3s.

The credentials were configured using default HID masterkeys, and can be picked up by the pm3's "hf iclass reader 1" command as well as iClassified. However, pm3 refuses to auth and read/write using the default HID masterkey, says 'auth failed'.

However, I managed to resolve it by first running calcnewkey on the credential to a new Kcus (old key being the default hid masterkey), rebooting to XP and iClassified and overwriting block 03 with the xor div key previously calculated. Then pm3 can finally read/write or even change the Kcus thereafter.

I've detailed more of my investigation here in my blog: … solved-it/

Anyone has any idea why this is so? Just feels really weird.

Last edited by thejoggingmat (2020-06-22 04:03:42)


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