Proxmark3 community

sina

Member

Registered: 2015-07-07

Posts: 2

Memory structure of Ultralight cards

Hello everyone,

This is my first post and I'm very noob at RFID so please have patience

I have a friend who works in a company where they have access control by RFID cards. Now he wants to put the tag on a chip that he can inject into his hand. But he can't get it to work and he has asked me for help, so I'm trying to trouble shoot the issue.

First of all when I ask him what type of card it is he says he has scanned it with the reader on an Android and the app says it is an Ultralight. But when I asked him to post the memory content he sent me this:

000  00 00 00 01 00 00 00 01 00 00 00 10 00 00 00 04
010  00 00 00 00 00 00 00 04 04 5D 5C 8D 00 00 00 04
020  00 00 00 01 00 00 00 04 7A 85 24 80 00 00 00 05
030  00 00 00 00 00 00 00 04 5B 48 FF FF 00 00 00 00
040  02 00 00 00 02 00 00 00 03 00 00 00 03 00 00 00
050  04 00 00 00 00 00 00 00 00 00 00 00 00 04 00 00
060  00 01 00 00 00 04 00 00 00 04 53 4B 45 42 01 00
070  00 00 01 00 00 00 05 00 00 00 04 42 31 32 32 01
080  00 00 00 01 00 00 00 06 00 00 00 04 30 34 30 30
090  01 00 00 00 01 00 00 00 07 00 00 00 04 33 33 53
0A0  45 01 00 00 00 01 00 00 00 08 00 00 00 04 32 30
0B0  31 32 01 00 00 00 01 00 00 00 09 00 00 00 04 00
0C0  00 00 00 01 00 00 00 01 00 00 00 0A 00 00 00 04
0D0  00 00 00 00 01 00 00 00 01 00 00 00 0B 00 00 00
0E0  04 00 00 00 00 01 00 00 00 01 00 00 00 0C 00 00
0F0  00 04 00 00 00 00 01 00 00 00 01 00 00 00 0D 00
100  00 00 04 00 00 00 00 01 00 00 00 01 00 00 00 0E
110  00 00 00 04 00 00 00 00 01 00 00 00 01 00 00 00
120  0F 00 00 00 04 00 00 00 00 01

But I know Ultralights are only 16 pages of 4 bytes of memory on each page, so can this really be an Ultralight? I have read the product sheets of the Ultralights and I can't find any clues. Is the app wrong or have I missed something about the memory structure of Ultralights? I don't know how I should proceed from this point. If anyone has any suggestions it would be really appreciated.

midnitesnake

Contributor

Registered: 2012-05-11

Posts: 151

Re: Memory structure of Ultralight cards

looks like you used a tool that failed to honour the ultralight boundaries, the data has wrapped & duplicated several times.  Change the reader and/or android phone rfid software.

Try reading the tag again with - "NFC TagWriter by NXP"

sina

Member

Registered: 2015-07-07

Posts: 2

Re: Memory structure of Ultralight cards

Yeah, you were right. It was probably the app because NFC TagInfo (by NXP) had no trouble reading it as it should. Thanks!