🍦 ItyFuzz

[\[Docs\]](https://docs.ityfuzz.rs) / [\[Research Paper\]](https://dl.acm.org/doi/pdf/10.1145/3597926.3598059) / [\[Twitter\]](https://twitter.com/fuzzland_) / [\[Discord\]](https://discord.com/invite/qQa436VEwt) / [\[Telegram\]](https://t.me/fuzzland)

ItyFuzz is a blazing-fast EVM and MoveVM smart contract hybrid fuzzer that combines symbolic execution and fuzzing to find bugs in smart contracts offchain and onchain.

Install

curl -L https://ity.fuzz.land/ | bash
ityfuzzup

Example

Fuzzing Deployed Smart Contract

Generating full exploit to steal funds from a contract with flashloan + read-only reentrancy vulnerability on Polygon.

# Fork Polygon at block 35718198 and fuzz the contract
ETHRPCURL=https://polygon-rpc.com ityfuzz evm\
    -t 0xbcf6e9d27bf95f3f5eddb93c38656d684317d5b4,0x5d6c48f05ad0fde3f64bab50628637d73b1eb0bb\
    -c polygon\
    --flashloan\
    --onchain-block-number 35718198\
    --onchain-etherscan-api-key TR24XDQF35QCNK9PZBV8XEH2XRSWTPWFWT # <-- Get your own API key at https://polygonscan.com/apis if this one is rate limited

Foundry Invariant Test

Run a Foundry invariant test defined in Invariant contract in test/Invariant.sol.

# Replaces: forge test --mc test/Invariant.sol:Invariant
ityfuzz evm -m test/Invariant.sol:Invariant -- forge test

For other examples and usages, check out the docs.

Performance

On large real-world smart contract projects, ItyFuzz finds 126 vulnerabilities while Echidna finds 0 and Mythril finds 9. For details, refer to backtesting, research paper, and new bugs discovered.

On small real-world smart contracts (ERC20, lottery, etc.), ItyFuzz gains 10% more test coverage than academia state-of-the-art fuzzer SMARTIAN using 1/30 of the time.

On Consensys's Daedaluzz benchmark, ItyFuzz without symbolic execution finds 44% more bugs than Echidna and 31% more bugs than Foundry. ItyFuzz is also 2.5x faster than Echidna and 1.5x faster than Foundry.

Features

• Chain forking to fuzz contracts on any chain at any block number.
• Accurate exploit generation for precision loss, integer overflow, fund stealing, Uniswap pair misuse etc.
• Reentrancy support to concretely leverage potential reentrancy opportunities for exploring more code paths.
• Blazing fast power scheduling to prioritize fuzzing on code that is more likely to have bugs.
• Symbolic execution to generate test cases that cover more code paths than fuzzing alone.
• Flashloan support assuming attackers have infinite funds to exploit flashloan vulnerabilities.
• Liquidation support to simulate buying and selling any token from liquidity pools during fuzzing.
• Decompilation support for fuzzing contracts without source code.
• Supports complex contracts initialization using Foundry setup script, forking Anvil RPC, or providing a JSON config file.
• Backed by SOTA fuzzing engine LibAFL.

Bugs Found

Selected new vulnerabilities found:

| Project | Vulnerability | Assets at Risks | | --- | --- | --- | | BSC $rats NFT | Integer overflow leading to unlimited minting | $79k | | 9419 Token | Incorrect logic leading to price manipulation | $35k | | BSC Mevbot | Unguarded DPPFlashLoanCall | $19k | | FreeCash | Incorrect logic leading to price manipulation | $12k | | 0xnoob Token | Incorrect logic leading to price manipulation | $7k | | Baby Wojak Token | Incorrect logic leading to price manipulation | $4k | | Arrow | Incorrect position logic leading to fund loss | Found During Audit |

ItyFuzz can automatically generate exploits for >80% of previous hacks without any knowledge of the hack. Refer to backtesting for running previously hacked protocols.

Sponsors & Grants

• Manifold Finance
• Sui