RP2350 Hacking Challenge

Welcome to the Raspberry Pi RP2350 hacking challenge and bug bounty!

Watch our quick explainer video:

Update Sept 5th 2024

No breaks have been reported yet.
We are doubling the prize to $20,000!
We've extended the term of the challenge, it now runs until midnight on December 31st 2024 (UK time)

The goal is easy: Find an attack that lets you dump a secret hidden in OTP ROW 0xc08 - the secret is 128-bit long, and protected by OTP_DATA_PAGE48_LOCK1 and RP2350's secure boot!

If you think you have found a break email us at [email protected] with details - we will ship you a Pico2 with a custom secret hidden in it. If you manage to extract it, you win the $20,000!

Good luck!

Disclaimer

For this challenge we will do the following persistent & irreversible changes to your RP2350:

• Writing bootkey0 (with a public key - or you can generate your own & build your own firmware)
• Enabling secure-boot via crit1.secure_boot_enable (but with public keys)
• Disable debug via crit1.debug_disable
• Overwrite & lock data in OTP ROW 0xc08
• Enabling security will permanently disable both Hazard3 RISC-V cores (M33 cores will still be operable)

Setup - Pico 2 board

• Connect an RP2350 in BOOTSEL mode to your computer via USB
• The repository already contains signing keys: ec_private_key.pem and ec_public_key.pem. If you want to generate your own keys you can run keygen.sh to generate new ones using openSSL.
• Next we write the secret that we want to hide using: ./write_otp_secret.sh - this is irreversible, as we can't "erase" OTP.
• You can check whether this write was successful by running ./read_otp_secret.sh
• Next we build our project:
  • mkdir build
  • cd build
  • cmake -DPICO_PLATFORM=rp2350 -DPICO_BOARD=pico2 ..
  • make
  • cd ..
• Next we enable secure-boot on the chip by running enable_secureboot.sh (This irreversibly enables secure-boot! Make sure you keep a backup of your keys!)
  • To fully lock down the chip including disabling debugging and enabling the glitch detectors, please run lock_chip.sh
• And now we are ready to install the firmware:
  • Either copy rp2350_hacking_challenge_debug_version.uf2 or rp2350_hacking_challenge_secure_version.uf2

What's the difference between the debug and the secure version?

The debug version shows how to read the OTP secret that you need to extract, and also gives some debug output on what's going on in the chip.

As the printfs etc. might be susceptible to fault-injection attacks we have disabled them in the secure version.

Our "golden" challenge Pico 2 will run the secure-version of the firmware, with the binary copied to RAM.

Using the chip in the future

By participating in this challenge you are permanently enabling secure-boot on your device. Any firmware you want to install in the firmware you need to sign yourself. You can enable signing for other projects by simply adding this to the CMakeLists.txt (this needs to be above the pico_add_extra_outputs) and copying the ec_private_key.pem to your source directoy.

# Signing and hashing
pico_sign_binary(project_name ${CMAKE_CURRENT_SOURCE_DIR}/ec_private_key.pem)
pico_hash_binary(project_name)
pico_set_otp_key_output_file(project_name ${CMAKE_CURRENT_LIST_DIR}/otp.json)

Rules, Terms and Conditions

Please see here for terms, conditions and rules for this challenge.