Proxmark3 community

Rocket9

Contributor

Registered: 2014-02-13

Posts: 9

Need help identifying unknow tag

Hello,

I need help to identify a tag. I'm using Proxmark3 since few weeks and had already managed to read and clone Mifare or HID cards, but this new tag is a mystery for me. It's a tag used to access a carpark.

Here's what the hw tune says :

Without tag :
         
proxmark3> # LF antenna: 15.44 V @   125.00 kHz         
proxmark3> # LF antenna: 15.44 V @   134.00 kHz         
proxmark3> # LF optimal: 21.08 V @   129.03 kHz         
proxmark3> # HF antenna:  0.00 V @    13.56 MHz         
proxmark3> # Your HF antenna is unusable.

with tag :
       
proxmark3> # LF antenna: 12.89 V @   125.00 kHz         
proxmark3> # LF antenna: 16.38 V @   134.00 kHz         
proxmark3> # LF optimal: 18.66 V @   130.43 kHz         
proxmark3> # HF antenna:  0.00 V @    13.56 MHz         
proxmark3> # Your HF antenna is unusable.

without tag :

proxmark3> # LF antenna:  0.00 V @   125.00 kHz         
proxmark3> # LF antenna:  0.00 V @   134.00 kHz         
proxmark3> # LF optimal:  0.00 V @ 12000.00 kHz         
proxmark3> # HF antenna: 11.76 V @    13.56 MHz         
proxmark3> # Your LF antenna is unusable.         

with tag :
                       
proxmark3> # LF antenna:  0.00 V @   125.00 kHz         
proxmark3> # LF antenna:  0.00 V @   134.00 kHz         
proxmark3> # LF optimal:  0.00 V @ 12000.00 kHz         
proxmark3> # HF antenna: 11.09 V @    13.56 MHz         
proxmark3> # Your LF antenna is unusable.

I suppose this is a 125 kHz ?

http://www.sendspace.com/file/s5v8qk = Here is the file obtained with that command :

proxmark3> lf read
#db# buffer samples: 73 74 73 73 73 74 73 74 ...                 
proxmark3>
proxmark3> data samples 16000
Reading 16000 samples
Done!

The "data plot" result is very strange. How can I post the image ? The forum said "You are not allowed to post links". http://hpics.li/6c311ea

What do you think about it ? Thanks a lot for your help.

asper

Contributor

Registered: 2008-08-24

Posts: 1,409

Re: Need help identifying unknow tag

It is a 125kHz tag; you can try to read it as an EM4100 tag (use specific pm3 command). If it doesn't work maybe it does not transmit data until a query is sent by the reader (anyway the signal seems to be almost absent in the plot-picture you take - here some 125kHz samples). To dig out more info you can link to a picture of the card.

Last edited by asper (2014-02-13 18:39:25)

Rocket9

Contributor

Registered: 2014-02-13

Posts: 9

Re: Need help identifying unknow tag

Hello Asper and thanks for your reply,

Here's some pictures of the tag :

http://hpics.li/0c1dffa

http://hpics.li/ba8548b

Trying to read it as an EM41xx doesn't work. When using the command "lf em4x em410xwatch", the tag is not detected. Do you suggest to snoop the communication between the tag and the reader ?

marshmellow

Contributor

From: US

Registered: 2013-06-10

Posts: 2,302

Re: Need help identifying unknow tag

the data plot appears like it is not receiving any data.  are you sure this is a working tag?
it may draw power but if it was damaged it may not transmit anything.

Rocket9

Contributor

Registered: 2014-02-13

Posts: 9

Re: Need help identifying unknow tag

Yes the tag is working, I use it everyday to access my carpark. Could it be a different frequency ? Perhaps 134 kHZ ? Or a uncommon proprietary tag ?

marshmellow

Contributor

From: US

Registered: 2013-06-10

Posts: 2,302

Re: Need help identifying unknow tag

seems very strange.  I'd guess a tag of a different frequency, perhaps 150kHz?  unless there is an antenna issue it appears it is an uncommon chip.