• Mifare Crack

In this blog post I will cover some quick basics about NFC, Mifare Classic and how to set up everything for reading and writing a NFC tag. Free program hotel california ukulele tab pdf. At the end I show you how to reprogram a vending machine’s NFC tag to contain more credits. NFC stands for Near Field Communication and is used to communicate over short distances. For more Infos on NFC you can read the. NFC nowadays is used for access cards, public transport, some more and in this case: Vending Machines. Basically there is an active NFC enabled device (the reader) and a passive device (the tag). The active device scans for the passive one and establishes a connection on contact.

It also powers the passive device via an electromagnetic field. There is also an active - active mode where both endpoints can send data and need to be powered seperately. This is usually used when sending data for example in “Android Beam”. In this example the vending machine has an active NFC reader built in. You can touch it with your tag to buy some drinks and the corresponding price is subtracted from the ammount stored on the tag. You can also recharge your tag via the machine if you run out of credits.

Mifare Crack

The NFC tag I analyzed is a so called “Mifare Classic 1k” tag. 1k stands for the size of data the tag can store. There are also other types like the “Mifare Classic 4k” and the “Mifare Mini” each having a different memory size. Mifare Classic in general is stated insecure, because it’s encryption protocol has been cracked. More deatiled Information about this can be found in the following links: A Mifare Classic 1k tag contains 16 sectors. Each of these sectors has 3 blocks of data storage and 1 block for storing the secret access keys and access controls.

Each block contains 16 bytes of data. Before reading a sector, the reader must authenticate to the tag with a secret access key. Each sector has two keys: Key A and Key B Each of the 16 sectors can define it’s own access right and wich key is needed for a particular action. As an example you can define to use Key A for reading the block and Key B for writing to it. Sector 0 Block 0 also contains a non changeable UID (the tags unique ID) and some manufacturer data. This section is only writeable on some special chinese tags.

Hackers, start your microscopes? The MiFare RFID hack, writes Geeta Dayal, used a few tools not in the arsenal of your average code-duffer. But now that researchers.

Here is a basically memory layout of a Mifare Classic tag: (taken from the Mifare Datasheet, link see below) More about Mifare in general can be found on. For more information on Mifare 1k Tags, the memory layout and more details you can visit these pages: Now I will demonstrate how to get all access keys for all sectors, locate the credits and modify them. For this example I used the connected via an and as an alternative a Raspberry Pi with the PN352 Breakout Board. These items can be purchased from various online shops around the world. For connection instructions on the Raspberry Pi please refer to.

Important notice: NFC and the used attack depend a lot on timing. Connecting a NFC device to a VM running linux will not work reliable because the drivers mess with this timing. I spent a lot of time finding this out, so please boot into a linux live cd for the following example or use a Raspberry Pi. Here are the basics to set your machine up for getting the access keys. The first step is to set up libnfc so the OS can communicate with the NFC reader. You can get the latest libnfc version from.

At the time of writing the current version was 1.7.1.