Locking Hands: Ransomware Meets Bioimplants

Mauro Eldritch presented LockSkin, an educational ransomware experiment aimed at NFC bioimplants, the small subdermal chips some people inject into their hands to unlock doors, cars and devices. He noted that many owners skip a password or choose an easy one, which became the entry point for the work.

Reverse engineering was central: implant memory is tiny, and the password is stored as a short four-byte transform that each application computes with its own proprietary function, so only the originating tool can verify it. The team dumped and compared memory from encrypted and unencrypted tags, using an AI model to spot differences, and avoided permanent lock pages. Practical hurdles followed: limited reader range, a custom build inside a door knob with a PN532 reader and an ESP32, tight memory, and log retrieval over Wi-Fi. Several test tags were bricked.

The talk closed with a decryptor that sends raw NFC commands using the known password to reset the tag, showing the damage is reversible. Takeaways: treat implant passwords as a real control, know which memory regions are permanent before writing, and expect new interfaces to add attack surface.