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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.
Generating full exploit to steal funds from a contract with flashloan + read-only reentrancy vulnerability on Polygon.
# Install ItyFuzz
curl -L https://ity.fuzz.land/ | bash
ityfuzzup
# Fork Polygon at block 35718198 and fuzz the contract
ETH_RPC_URL=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 For other examples and usages, check out the docs.
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.
- 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 Web2 fuzzing engine LibAFL.
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 posiition 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.