Rhinestone ERC-7579 Adapter Audit Summary and Findings Report

Rhinestone’s ERC-7579 adapter for Safe smart accounts ensures complete compliance with ERC-4337 and ERC-7579, functioning as both Safe’s Fallback handler and an enabled module. This configuration allows all Safe smart accounts to leverage the capabilities of ERC-7579 modules. The adapter can be integrated into existing Safe smart accounts, and a launchpad has also been created to facilitate the establishment of new Safe smart accounts with the ERC-7579 adapter pre-enabled.

Rhinestone engaged Ackee Blockchain Security for a comprehensive security review of the Rhinestone ERC-7570 adapter for Safe smart accounts, spanning a total of 16 engineering days from June 3 to June 14, 2024.

Additionally, Rhinestone enlisted Ackee Blockchain Security to conduct an incremental security review of an updated Safe7579 module, dedicating 3 engineering days from July 2 to July 5, 2024.

METHODOLOGY

Our review commenced with static analysis tools, utilizing Wake in conjunction with the Solidity (Wake) VS Code extension. We then conducted an in-depth analysis of the contract logic. For testing and fuzzing, we employed the Wake testing framework. Throughout the review, we focused on:

• verifying Safe deployment via the Launchpad,
• assessing module management logic and the installation of various module types,
• evaluating fallback handler implementation,
• identifying potential DoS scenarios,
• examining front-running vulnerabilities,
• ensuring the correct use of delegatecalls,
• detecting potential reentrancy risks within the code,
• verifying compliance with the utilized ERCs,
• ensuring proper access control measures are enforced,
• identifying common issues, including data validation errors.

SCOPE

The audit was conducted on the commit 90dd363, with the following scope:

• core/
  • AccessControl.sol
  • ExecutionHelper.sol
  • Initializer.sol
  • ModuleManager.sol
  • RegistryAdapter.sol
  • SetupDCUtil.sol
• lib/
  • ExecutionLib.sol
  • ModeLib.sol
• utils/
  • DCUtil.sol
  • Safe7579UserOperationBuilder.sol
• DataTypes.sol
• Safe7579.sol
• Safe7579Launchpad.sol

FINDINGS

Below are the findings from our audit.

Critical severity

C1: ERC-4337 counterfactual address vulnerability leading to potential theft

High severity

H1: initializeAccount susceptible to front-running

H2: Inability to utilize Executors

Medium severity

M1: Event and onInstall invocation absent in _initModules

M2: BatchedExecUtil._tryExecute success value inverted

M3: Single return value in BatchedExecUtil.tryExecute

M4: ModuleManager._installHook SIG hook being overwritten

M5: Ether locked without a method to retrieve

Low severity

L1: Validation issues with fallback handler CallType

L2: Missing domain-specific message encoding in signedMessages

L3: Violation of ERC-4337 factory standards

L4: Validation deficiencies for _multiTypeInstall module type

Warning severity

W1: postCheck function diverges from EIP-7579 interface

W2: uninstallModule fails on multi-type module

W3: Hook functionality may obstruct module uninstallation

W4: Absence of necessary data validations

W5: Public function prefixing with underscore

W6: Hardcoded Enum.Operation values present

W7: Incomplete Safe7579UserOperationBuilder implementation

W8: Lack of TryExecutionFailed emit statements

Information severity

I1: Instances of duplicated code

I2: Unused code segments

I3: Typographical errors and inaccuracies in documentation

I4: Issues with overall code structure

W9: Safe lacking implementation of validator interface

W10: Inconsistent checking of signatures

I5: Unneeded usage of using-for

I6: Typographical error detected

CONCLUSION

Our review identified 28 findings, categorized from Informational to Critical severity. The most significant issue allows an attacker to potentially control Safe deployments via the Launchpad (refer to C1). Additional high-severity issues are related to the front-running risk associated with the Safe7579.initializeAccount function (H1) and the improper context in the withRegistry modifier within the Safe7579.executeFromExecutor function (H2). The medium severity findings include mostly overlooked trivial errors. Overall, the code quality is average, with some TODO comments, unused code, and a lack of comprehensive NatSpec documentation.

 

Ackee Blockchain Security advises Rhinestone to:

• address the potential for newly deployed Safe takeovers,
• protect the Safe7579.initializeAccount function from front-running vulnerabilities,
• correct the context in the withRegistry modifier within Safe7579.executeFromExecutor,
• resolve the SIG hooks that are being overridden,
• fix batch execution return value issues,
• invoke the module onInstall function during the _initModule process,
• eliminate all TODOs and remove any unused code,
• ensure the entire codebase is covered with NatSpec documentation,
• attend to all remaining reported issues,
• additionally, we suggest ongoing internal peer code reviews.

 

The complete audit report from Ackee Blockchain Security for Rhinestone, detailing all findings and recommendations, is available here.

 

We were pleased to conduct the audit for Rhinestone and look forward to future collaborations.