Resources

People often ask me "How did you learn how to hack?" The answer: by reading. This page is a collection of the blog posts and other articles that I have accumulated over the years of my journey. Enjoy!

Nespresso is a popular coffee machine that has custom smart cards in an office setting. These smart cards are using the known vulnerable mifare classic brand.

The author, knowing the cards were by default vulnerable, made an assumption that data was being stored on the smart card (and not on a server). Once the author made this assumption, they attempted to crack the keys of the smart card using known software.

However, this software had some issues. So, the author posted a few pull requests to get the key extraction process to work. Now, the encryption keys for the cards were cracked.

If the money is stored on the card, how do we know where? Simple: view, make a transaction then see what values change. By knowing how much money was on the card, purchasing something, then checking the value again, the binary dump showed where to alter.

Using some of the already available tools, the author set the money value to a ridiculously high number that was not even possible to display on the coffee machine (lolz). Pwnage complete!

The mitigations for this issue would be to use newer smart cards or store the data server-side. When the author disclosed to Nespresso they already offered by in newer products.