bbenzikry/malleable-signature-demo

ECDSA signatures are malleable

Details: https://www.derpturkey.com/inherent-malleability-of-ecdsa-signatures From the article:

It allows anyone to modify the signature in a specific way without access to the private key and yet the signature remains perfectly valid!

Go to SignVerifierTest.t.sol to see how you can change the signature for Ethereum's Secp256k1 curve. Once someone signs a message and produces a signature, just using the signature, you can create another signature that is perfectly valid (that is ecrecover will tell you the original signer signed it).

Steps to run

• forge install (Install foundry if you haven't).
• forge test -vv and two same addresses should be printed on screen.

Be safe

You can be safe from these footguns by using OpenZeppelin's ECDSA library instead of the vanilla ecrecover operation.

Please note that just using this library won't protect you from all signature vulnerabilities.