Writing to XNT After Password Protection w/DT App

#1

Hi everyone, looking for some help with my XNT. After installing I wrote a pin/password to my implant using the Dangerous Things app. Now that I’ve written the password to it I’m having a hard time using other apps to actually write to the XNT. I’ve attempted to use both the NFC Tools App and the NXP TagWriter App with the password options enabled. I’m using the Essential Phone PH-1 running Android 9.0. All I really want to do is set my tag up to launch an HTTP hyperlink, but all of the apps give me write errors, I’m assuming because of the password protection from the DT App.

Is there some way to just completely reset the tag, remove the DT App’s password and use the NFC Tools or TagWriter App’s built in password option? I have read a few other threads that have mentioned using NFC Shell commands, but I’m really not familiar with the application enough to mess around without some sort of tutorial. I also have a PM3 Easy, but per my understanding the model I ordered has a 125khz antenna. Not sure what my strategy should be here, just want to make sure I don’t brick my chip somehow, appreciate any advice you guys can give, cheers!

Can my xNT be easily set to read-only?
#2

Here’s my tag info from the DT Support App in case that’s of any help.

Get Version:
00 04 04 02 01 00 13 03
Page 00: 04 58 E1 35
Page 01: 32 0A 54 81
Page 02: ED 48 0F 00
Page 03: E1 12 6D 00
Page 04: 03 00 FE 00
Page 05: 00 00 00 00

Page E2 :00 00 7F BD
Page E3 :04 00 00 E2
Page E4 :00 05 00 00

#3

You don’t really want to use the others apps password option imo, they all do it in various funky ways and don’t seem to actually respect standards.

Is there any other NFC device you can get your hands on to see if this is a bug with the essential phone? Just to test the NXP or NFCTools app ideally.

#4

Really the answer is that we need to update the Dangerous NFC app to handle things properly… but it’s a little bit like re-inventing the wheel since so many other apps already do a ton of stuff… it’s still just annoying because they don’t do it correctly and we don’t have the bandwidth to try to make them fix theirs or duplicate what they’ve done…

We will try to get the DNFC app updated to support basic stuff like password changes and basic record writing.

#5

I will give that a shot, but if that isn’t the case, have a bricked my xNT? Just by using the DT App?

#6

So I’ve now attempted using the NXP Writer with the essential phone, Galaxy Note 9 and Galaxy S8, none have worked while using the password I set in the Dangerous Things app. What’s my next step for being able to write to this or doing a factory reset?

#7

Sorry can you explain the part about the password? That should just lock the config bits of your implant from what I understand, You sure you know the right password?

#8

There are other posts.on the forum about this but I’ll just summarize… NFC Tools and other apps don’t write the password as typed to the chip. They do some kind of transform on it. As such, when we write the legitimate characters you type as the password, NFC Tools can’t authenticate that password when you give it to NFC Tools to unlock password updating. It’s very annoying.

#9

The first thing I did with my xNT before attempting to write anything to it, was use the DT App to set a password on it. From there I attempted to write using the NXP Tag Writer app which has an option when writing to use the existing password for the tag, which did not work. No options in either the NXP App or NFC Tools has allowed me to write to the tag. I 100% know the password I set using the DT App.

#10

I didn’t use NFC Tools to write the password though, I used the dangerous things app. All I’ve attempted to do after that I then use either NFC Tools or the NXP Tag Writer app to write to my implant. At this point the only thing I’ve done to the implant is password protect it with the DT App, and have been unable to do anything with it since. All I’m trying to figure out, is what are my next steps. Is there a way to remove the password? Is there some app that will allow me to write to the tag with the password I set using the DT app? What options do I have moving forward that will allow me to actually use the tag, rather than just have it be a password protected lump in my hand? If the answer is learn command line commands for NFC tags and purchase a particular revision of the Proxmark 3 that’s fine, I just need to know, 'cause I’m completely lost on what I’ve done wrong or what I should be doing to enable writing to this thing.

#11

The password protection you used on the DT app didn’t write protect the whole of the tag. Just the configuration “bits”. You should be able to write to the using TagWriter without specifying a password?

#12

The error I receive when attempting to write using the TagWriter app when not using the current password option is that it is not a supported tag, and a dialog box that shows a list of all the compatible tags it can write to. I will attempt it again tonight with screenshots of my attempts with NFC Tools and NXP Tag Writer.

#13

Thought I’d give an update on this, I did manage to finally write to my xNT, I had to do a full reset and re-install of Anroid on my essential phone but it did eventually work. I will definitely confirm though that I had a fundamental misunderstanding of the purpose and function of the DT App setting a password. I thought I had read enough forum threads and videos to understand what was going on, but it turns out I was hugely over thinking it. That said, it definitely wouldn’t be the worst thing in the world to update the DT app to be a bit more clear on the functionality of setting the password, and that using that password to grant write permission every time is not needed/at all how it works for actually writing to your tag. Thanks to everyone in the thread for trying to help with this, cheers!