├── .github └── workflows │ └── link-check.yml ├── LICENSE ├── README.md └── mlc_config.json /.github/workflows/link-check.yml: -------------------------------------------------------------------------------- 1 | name: Check Markdown links 2 | 3 | on: [push, pull_request] 4 | 5 | jobs: 6 | markdown-link-check: 7 | runs-on: ubuntu-latest 8 | steps: 9 | - uses: actions/checkout@master 10 | - uses: gaurav-nelson/github-action-markdown-link-check@v1 11 | with: 12 | config-file: 'mlc_config.json' 13 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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A call to an address with no bytecode will not revert, and a contract with a fallback function will call the fallback function when an undeclared function is called ([Dedaub Phantom Functions research](https://media.dedaub.com/phantom-functions-and-the-billion-dollar-no-op-c56f062ae49f)). 7 | 8 | ## Swap is performed 9 | - Check for frontrunning and sandwich attack of the swap. This can happen when interacting with any liquidity pool (Uniswap, Sushi, Curve, Balancer, etc.) 10 | - If a one-sided swap is performed before depositing into the liquidity pool (often named a "zap"), there may be [dust left over](https://blog.alphaventuredao.io/onesideduniswap/) because the first one-sided swap alters the balance and price of the liquidity pool assets. 11 | 12 | ## transferFrom is used 13 | - If tokens are transferred from a contract address, that contract must approve the tokens before the transferFrom is called, otherwise it will revert 14 | 15 | ## Overflows 16 | - Safe math in Solidity 0.8.X does not protect against integer casting overflows and bitshift overflows 17 | 18 | ## Gas griefing / denial of service 19 | - Check all `require` and `revert` logic in case of unintentional reverts causing the user loss of gas 20 | 21 | ## ecrecover 22 | - Standard solidity ecrecover function is used without checking if the result is the zero address. Must check for zero address or use OZ `recover` from ECDSA library. 23 | 24 | ## ERC20 25 | - If any ERC20 token is supported by the protocol (meaning tokens are not whitelisted), check for [weird ERC20 edge cases](https://github.com/d-xo/weird-erc20) 26 | - If an ERC20 token list is used it must consider double entry point tokens, with past issues of this type [here](https://medium.com/chainsecurity/trueusd-compound-vulnerability-bc5b696d29e2) and [here](https://forum.balancer.fi/t/medium-severity-bug-found/3161) 27 | 28 | ## ERC721 29 | - The ERC721 tokenId value must be unique. If the tokenId value is not a simple incrementing counter and instead uses a formula to calculate the tokenId, duplicate values may occur and lead to a revert 30 | - If safeMint is used, check for reentrancy on the callback hook 31 | 32 | ## Access controls 33 | - If any access controls are used (often in the form of modifiers) check functions that do not have any modifier to see if the modifier may have been forgotten. 34 | 35 | ## External price data is used 36 | - If spot price of a liquidity pool is used... [just no](https://shouldiusespotpriceasmyoracle.com/) 37 | - Chainlink oracle data may be stale. The roundId and timestamp should be checked. 38 | 39 | ## AMM/DEX 40 | - Any purchase or swap function should have slippage protection. This is normally a user-specified function argument. 41 | - If a contract facilitates deposits into a DEX like Uniswap and tracks user positions with shares, the first deposit into this pair of the protocol [could be frontrun](https://media.dedaub.com/latent-bugs-in-billion-plus-dollar-code-c2e67a25b689#3b16) 42 | 43 | ## Compound forks 44 | - Compound does not strictly follow the checks-effects-interactions pattern to avoid reentrancy. This can lead to reentrancy problems [if tokens with callbacks](https://twitter.com/Hacxyk/status/1520370424680304640) (ERC721, ERC777, etc.) are used. 45 | - Compound whitelists tokens and can avoid ERC20 tokens with unusual behavior. If a fork of compound does not whitelist tokens, issues can exist with [fee-on-transfer tokens](https://github.com/d-xo/weird-erc20#fee-on-transfer) among others. 46 | 47 | ## Proxies 48 | 49 | - UUPS proxies MUST be initialized after deployment. Forgetting to initialize the proxy led to [the first $10 million bug](https://medium.com/immunefi/wormhole-uninitialized-proxy-bugfix-review-90250c41a43a) from Immunefi and [many other past bugs](https://proxies.yacademy.dev/pages/security-guide/#bug-bounties). 50 | - State variable layout must be followed when delegatecall is used, otherwise this [leads to problems](https://proxies.yacademy.dev/pages/security-guide/#storage-collision-vulnerability) 51 | - Full list of common proxy bugs is at [proxies.yacademy.dev](https://proxies.yacademy.dev/pages/security-guide/) 52 | 53 | ## OpenZeppelin Upgradeable imports 54 | - Many OpenZeppelin upgradeable contracts need to be initialized in the importing contract's constructor. 55 | 56 | ## Voting and rewards/yield 57 | - Does the snapshot process prevent a user from flashloaning tokens to make a large number of votes or receive a lot of yield? 58 | - Does the snapshot process prevent a user from voting (or redeeming yield), transferring tokens, and voting again (or redeeming yield)? 59 | - If the voting happens off-chain, is proper planning and integration with snapshot.org applied? Which voting strategy is used? Will [voting delegation be added](https://docs.snapshot.org/guides/delegation#with-a-smart-contract) with the `setDelegate` function? 60 | 61 | ## Loan-related protocol 62 | - Is there a way that a user can become undercollateralized, reducing the incentive to pay their debt? 63 | 64 | ## NFT projects 65 | - If cryptopunks are supported (which requires custom code), it should protect against [this frontrun attack vector](https://blog.nftx.io/nftx-v2-punk-incident-post-mortem/). -------------------------------------------------------------------------------- /mlc_config.json: -------------------------------------------------------------------------------- 1 | { 2 | "retryCount": 3, 3 | "fallbackRetryDelay": "10s", 4 | "aliveStatusCodes": [200, 429] 5 | } 6 | --------------------------------------------------------------------------------