https://github.com/pcaversaccio/malleable-signatures

This repository implements a simplified PoC that demonstrates how signature malleability attacks using compact signatures can be executed.
https://github.com/pcaversaccio/malleable-signatures

ecdsa eip2098 exploit malleability signature-malleability

Last synced: 13 days ago
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This repository implements a simplified PoC that demonstrates how signature malleability attacks using compact signatures can be executed.

• Host: GitHub
• URL: https://github.com/pcaversaccio/malleable-signatures
• Owner: pcaversaccio
• License: wtfpl
• Created: 2023-06-10T17:37:01.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2024-10-26T18:18:27.000Z (18 days ago)
• Last Synced: 2024-10-26T20:17:24.974Z (18 days ago)
• Topics: ecdsa, eip2098, exploit, malleability, signature-malleability
• Language: Solidity
• Homepage:
• Size: 107 KB
• Stars: 106
• Watchers: 5
• Forks: 9
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Signature Malleability

[![Test smart contracts](https://github.com/pcaversaccio/malleable-signatures/actions/workflows/test.yml/badge.svg)](https://github.com/pcaversaccio/malleable-signatures/actions/workflows/test.yml)

[![License: WTFPL](https://img.shields.io/badge/License-WTFPL-blue.svg)](http://www.wtfpl.net/about)

This repository implements a simplified [PoC](./test/SignatureMalleability.t.sol) that demonstrates how signature malleability attacks using [compact signatures](https://eips.ethereum.org/EIPS/eip-2098) can be executed. The PoC showcases two interconnected issues:

1. A vulnerability with the [OpenZeppelin `4.6` ECDSA library](https://github.com/OpenZeppelin/openzeppelin-contracts/blob/release-v4.6/contracts/utils/cryptography/ECDSA.sol) which is vulnerable to the signature malleability exploit. The vulnerability was patched in version [`4.7.3`](https://github.com/OpenZeppelin/openzeppelin-contracts/releases/tag/v4.7.3). Also, see [here](https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-4h98-2769-gh6h) for the published security advisory.

2. Signatures MUST NOT be used as unique identifiers, since the [`ecrecover`](https://www.evm.codes/precompiled#0x01?fork=shanghai) precompile generally allows for malleable (non-unique) signatures (see [EIP-2](https://eips.ethereum.org/EIPS/eip-2)) or signatures can be malleablised using [EIP-2098](https://eips.ethereum.org/EIPS/eip-2098). The underlying issue in the `ecrecover` precompile stems from the fact that there are two `y`-coordinates for every `x`-coordinate on the elliptic curve. The OpenZeppelin ECDSA library prevents this particular malleability attack vector by reverting if the secp256k1 32-byte signature parameter `s` is too high.