29002 - [SC - Insight] Incorrect implementation of EIP- domain separat...
Submitted on Mar 4th 2024 at 13:58:49 UTC by @cheatcode for Boost | eBTC
Report ID: #29002
Report type: Smart Contract
Report severity: Insight
Target: https://github.com/ebtc-protocol/ebtc/blob/release-0.7/packages/contracts/contracts/BorrowerOperations.sol
Impacts:
Griefing (e.g. no profit motive for an attacker, but damage to the users or the protocol)
Description
Brief/Intro
See below
Vulnerability Details
EIP-712 provides a standard for signing typed structured data in Ethereum smart contracts, using the concept of domain separation to prevent collisions and replay attacks.
A key component of validation is the domain separator, which uniquely identifies the specific contract and chain for message signing purposes. The domain separator is constructed from:
DOMAIN_TYPEHASH: The keccak256 hash of the EIP-712 domain schema definition itself (the actual string types used like name, version etc.)
Contract Specific Values: Domain values like name, version, chain ID and contract address.
In the current contract, the _TYPE_HASH variable used in the domain separator construction does not match the expected DOMAIN_TYPEHASH. Upon closer inspection, it is aligned closer to the hash of the full message type itself rather than the domain type schema.
Impact Details
While this does not directly introduce security vulnerabilities per se, it indicates a gap in properly differentiating between DOMAIN_TYPEHASH and actual message TYPEHASH as EIP-712 expects
References
Add any relevant links to documentation or code
Proof of Concept
This could lead to the following issues:
Domain separators constructed incorrectly as per standards
Signatures validated against such separators fail externally
Mismatched assumptions between contract and clients
Confusing for future audit and maintenance
Recommendations
Introduce a properly defined DOMAIN_TYPEHASH constant
Construct domain separator by passing DOMAIN_TYPEHASH and contract-specific values
Optionally validate both DOMAIN_TYPEHASH and message TYPEHASH on chain
This will greatly improve standards compliance, clarity and future security.
Last updated