OpenZeppelin Contracts ECDSA bug

38 / Investigating the ECDSA bug in OpenZeppelin Contracts and searching for vulnerabilities in smart contracts. Will a zero day be found?

Episode notes

1. What is ECDSA?
   1. A public key and a private key
      1. Can be Eth address
   2. Sign a message with a private key, and anybody can verify against public key
      1. Sign a Eth TX or message
         1. The messages are used on smart contracts to denote authorization
   3. Encrypt message with a public key, and decrypt with a private key
   4. Two types of encoding, 64-byte and 65-byte
      1. Either is accepted for verification in a smart contract
2. ECDSA signature malleability · Advisory · OpenZeppelin/openzeppelin-contracts https://github.com/OpenZeppelin/openzeppelin-contracts/secur lity/advisories/GHSA-4h98-2769-gh6h
   1. OZ mentioned ecrecover opcode malleability
   2. OZ failed to mention the 64/65-bit malleability
   3. Reported other contracts affected ERC1271WalletMock and EIP712External
3. Should make signature acceptance injective rather than surjective
4. Need better code search for live contracts!
   1. At least github search accepts “-” operators
   2. Potential issues with Github search operators for Stars & Forks
5. Found a vulnerability in Zibert bridge (created Github issue) and Hive https://github.com/cent-inc/hive/issues/1