328p-flaw3d-bootloader
This repository contains a version of the FLAW3D bootloader used in the paper FLAW3D: A Trojan-based Cyber Attack on the Physical Outcomes of Additive Manufacturing, which is currently available from arXiv and was accepted in ASME/IEEE Transactions on Mechatronics.
For your convenience, the code which has been edited has been clearly labelled in the comments (Using /*** DEMO COMPROMISE CODE ***/ blocks).
Overall, FLAW3D serves as a proof of concept that bootloaders can be designed to interfere with the execution of microcontroller firmware even after the bootloaders are unloaded. In the paper, we use this as a mechanism to reduce the print quality of additively manufactured (3D printed) parts. However, to preserve the anonymity of the devices targeted, in this repository we present only the code for the basic FLAW3D bootloader, and not the complete compromise code.
This version of the FLAW3D bootloader is designed to target an ATmega328P running on an Xplained Mini 328P.
For a detailed explanation of the source code and its functionality, you can also read the associated blog post which steps through the modifications, has explanation figures, and even a demo video!
Executing this bootloader
Detailed steps for executing this code can be found with the associated blog post, however, the general steps are as follows:
- Download this repository
- Open the project file using Atmel Studio
- Customise the target ISRs in the bootloader
- Compile and install to an Xplained Mini 328P
- Install the Arduino IDE
- Install support for the Xplained Mini 328P to the Arduino IDE through the boards manager
- Write code to trigger your ISRs
- Observe how the Arduino ISR code is wrapped by the exploit code in the bootloader