Beanstalk: The Finale

Summary

The absence of access control in the diamondCut function introduces a significant security risk. An attacker could exploit this vulnerability to add malicious facets, remove critical facets, or replace legitimate facets with compromised versions, potentially compromising the diamond's intended functionality and user funds.

Vulnerability Details

• The diamondCut function is an internal function within LibDiamond, making it accessible to any contract inheriting from the library.

• There are no explicit checks within diamondCut to restrict who can invoke it.

• The function's logic directly modifies the diamond's state (adding, replacing, or removing facets) based on the input data.

Impact

A successful exploitation of this vulnerability could result in:

• Loss of Funds: An attacker could introduce a malicious facet that drains funds from the diamond contract.

• Denial of Service: Critical facets could be removed, rendering the diamond unusable.

• Manipulation of Functionality: Existing facets could be replaced with compromised versions that alter the diamond's intended behavior.

• Loss of Reputation: Users may lose trust in the diamond project due to security breaches.

Tools Used

Manual Code Review

Recommendations

Ownership-Based Access Control: Modify the diamondCut function to include a check that only allows the owner of the diamond contract to execute it. This can be achieved using the enforceIsContractOwner function within LibDiamond.

Multi-Signature/Timelock: Consider implementing a multi-signature scheme or a timelock mechanism to add an additional layer of security. This would require multiple authorized parties to agree on a diamond cut or delay the execution.