HARM: Hardware-assisted Continuous Re-randomization for Microcontrollers

Code reuse attacks are particuarly noteworthy in microcontroller-based embedded systems since the memory address of firmware code is static. This work seeks to combat code reuse attacks, including ROP and more advanced JIT-ROP via continuous randomization.

@inproceedings{harm,
  title={HARM: Hardware-Assisted Continuous Re-randomization for Microcontrollers},
  author={Shi, Jiameng and Guan, Le and Li, Wenqiang and Zhang, Dayou and Chen, Ping and Zhang, Ning},
  booktitle={2022 IEEE 7th European Symposium on Security and Privacy (EuroS\&P)},
  pages={520--536},
  year={2022},
  organization={IEEE}
}

HARM leverages TrustZone-M to isolate its secure runtime and firmware metadata from the target firmware code. Therefore, the target MCU processor must support ARMv8-M architecture and has security extension (i.e., TrustZone-M). Up to now, HARM is only tested under NXP LPC55S69 development board. Please extend HARM to support more vendors.

• Unix-like OS, Debian/Ubuntu is recommended
• Toolchain: GNU Arm Embedded Toolchain
• Debugger such as SEGGER J-Link, which is used to flash the target board

In this tutorial, we illustrate the usage of HARM under NXP LPC55S69 development board. First off, please clone HARM repository to your work directory.

git clone https://github.com/MCUSec/HARM.git
cd HARM

CMSE library is an ELF object file (named secure_rt_cmse.o) that contains the entry of the secure services (i.e., non-secure callable funtions that perform indirect calls, function returns, etc.). Calling of these functions will be instrumented to the target binary.

cd scripts
./extract_cmse.sh lpc55s69 # secure_rt_cmse.o will be generated

Please refer to the tutorial of harm-rwtool.

mkdir -p build && cd build
cmake -DTARGET_LPC55S69=On .. # LPC55s69 is the default option
make

After this step, you will get the binary of secure runtime named harm_secure_rt.elf. Then you can flash the secure runtime and the refined target binary to your NXP LPC55s69 development board.

You are welcomed to extend HARM to support more MCUs that satisfy the requirement. Please refer here for details.

If you encounter any problems with HARM, please open an issue. For other communications, please email jiameng @ uga.edu.

We are building a safer HARM with Rust to avoid potential memory errors in the HARM secure runtime. HARM-Rust is coming soon.