crytic / rattle

evm binary static analysis

rattle

Rattle is an EVM binary static analysis framework designed to work on deployed smart contracts. Rattle takes EVM byte strings, uses a flow-sensitive analysis to recover the original control flow graph, lifts the control flow graph into an SSA/infinite register form, and optimizes the SSA – removing DUPs, SWAPs, PUSHs, and POPs. The conversion from a stack machine to SSA form removes 60%+ of all EVM instructions and presents a much friendlier interface to those who wish to read the smart contracts they’re interacting with.

Example

python3 rattle-cli.py --input inputs/kingofether/KingOfTheEtherThrone.bin -O

Would produce a register machine output like this:

Functions are recovered and split off. Additionally function arguments, memory locations, and storage locations are recovered.

Usage

Rattle runs on the runtime contract hex string.

If you're running rattle on a contract you can compile with solidity, use the --bin-runtime option and strip off the header:

$ solc --bin-runtime KingOfTheEtherThrone.sol 2>/dev/null | tail -n1 > contract.bin

Dependencies

• python3
• graphviz
• cbor2
• pyevmasm

To install the python dependencies, run these commands:

python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt

To install graphviz, run the following command:

Linux:

sudo apt-get graphvis

macOS:

brew install graphviz

Troubleshooting

If you get a syntax error like this:

  File "rattle-cli.py", line 16
    def main() -> None:
               ^
SyntaxError: invalid syntax

You likely ran rattle with python2 instead of python3.

Presentation

For more details on the Rattle design and features, see my reCON Montreal presentation, which is annotated here.

License

Rattle is licensed and distributed under the AGPLv3 license. Contact us if you're looking for an exception to the terms.