Biconomy: Nexus

Summary

The executeUserOp function lacks proper input validation, which can lead to various security vulnerabilities, including incorrect execution logic, unexpected behaviors, and potential exploitation by malicious actors.

Vulnerability Details

The executeUserOp function directly decodes and executes the calldata provided in the PackedUserOperation. However, there is insufficient validation of the innerCall data extracted from userOp.callData. This lack of validation could allow malformed or malicious calldata to be processed, leading to unintended execution or reentrancy attacks.

Impact

An attacker could craft a malicious PackedUserOperation with specially designed innerCall data to:

• Exploit reentrancy vulnerabilities.

• Execute unintended or harmful operations within the contract.

• Manipulate contract state in unauthorized ways.

Tools Used

Manual Overview

Recommendations

• Implement strict validation checks on the innerCall data before executing it.

• Utilize the Checks-Effects-Interactions pattern to prevent reentrancy attacks.

• Consider using a reentrancy guard to further protect the contract from reentrancy exploits.