Mythril

Mythril is a security analysis tool for EVM bytecode. It detects security vulnerabilities in smart contracts built for Ethereum, Hedera, Quorum, Vechain, Roostock, Tron and other EVM-compatible blockchains. It uses symbolic execution, SMT solving and taint analysis to detect a variety of security vulnerabilities. It's also used (in combination with other tools and techniques) in the MythX security analysis platform.

If you are a smart contract developer, we recommend using MythX tools which are optimized for usability and cover a wider range of security issues.

Whether you want to contribute, need support, or want to learn what we have cooking for the future, our Discord server will serve your needs.

Installation and setup

Get it with Docker:

$ docker pull mythril/myth

Install from Pypi (Python 3.6-3.9):

$ pip3 install mythril

See the docs for more detailed instructions.

Usage

Run:

$ myth analyze <solidity-file>

Or:

$ myth analyze -a <contract-address>

Specify the maximum number of transaction to explore with -t <number>. You can also set a timeout with --execution-timeout <seconds>.

Here is an example of running Mythril on the file killbilly.sol which is in the solidity_examples directory for 3 transactions:

> myth a killbilly.sol -t 3
==== Unprotected Selfdestruct ====
SWC ID: 106
Severity: High
Contract: KillBilly
Function name: commencekilling()
PC address: 354
Estimated Gas Usage: 974 - 1399
Any sender can cause the contract to self-destruct.
Any sender can trigger execution of the SELFDESTRUCT instruction to destroy this contract account and withdraw its balance to an arbitrary address. Review the transaction trace generated for this issue and make sure that appropriate security controls are in place to prevent unrestricted access.
--------------------
In file: killbilly.sol:22

selfdestruct(msg.sender)

--------------------
Initial State:

Account: [CREATOR], balance: 0x2, nonce:0, storage:{}
Account: [ATTACKER], balance: 0x1001, nonce:0, storage:{}

Transaction Sequence:

Caller: [CREATOR], calldata: , decoded_data: , value: 0x0
Caller: [ATTACKER], function: killerize(address), txdata: 0x9fa299cc000000000000000000000000deadbeefdeadbeefdeadbeefdeadbeefdeadbeef, decoded_data: ('0xdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef',), value: 0x0
Caller: [ATTACKER], function: activatekillability(), txdata: 0x84057065, value: 0x0
Caller: [ATTACKER], function: commencekilling(), txdata: 0x7c11da20, value: 0x0

Instructions for using Mythril are found on the docs.

For support or general discussions please join the Mythril community on Discord.

Building the Documentation

Mythril's documentation is contained in the docs folder and is published to Read the Docs. It is based on Sphinx and can be built using the Makefile contained in the subdirectory:

cd docs
make html

This will create a build output directory containing the HTML output. Alternatively, PDF documentation can be built with make latexpdf. The available output format options can be seen with make help.

Vulnerability Remediation

Visit the Smart Contract Vulnerability Classification Registry to find detailed information and remediation guidance for the vulnerabilities reported.