Flow

Summary

The admin address in the Adminable contract is not initialized in the constructor, leading to potential functionality loss.

Finding Description

The Adminable contract requires an admin address to enforce access control through the onlyAdmin modifier. However, the admin variable is left uninitialized upon contract deployment, defaulting to zero (0x0). This oversight effectively renders all admin-only functions inoperable since msg.sender will never equal the uninitialized admin address, preventing legitimate calls from succeeding.

This vulnerability breaks the security guarantee of proper access control by allowing a scenario where no entity can perform administrative tasks, thus locking the contract's functionalities that require admin rights. A malicious actor could exploit this by deploying the contract without a valid admin, making the contract permanently unusable for admin functions.

Vulnerability Details

• Severity: High

• Vulnerability Type: Access Control

• Affected Functionality: All functions guarded by the onlyAdmin modifier.

The problem originates from the lack of a constructor or a mechanism to set the admin address during deployment. Without a valid admin address, the contract remains in a locked state.

Impact

The inability to set an admin address upon contract deployment significantly affects the contract's functionality and its operational integrity. It could prevent essential administrative actions, such as upgrading the contract or adjusting critical parameters, thereby leading to a denial of service for legitimate users.

Proof of Concept

Here’s a snippet of the existing code that showcases the lack of initialization:

Upon deploying this contract, the admin will be 0x0, leading to failure in all onlyAdmin checks:

Recommendations

To resolve this issue, implement a constructor in the Adminable contract to initialize the admin address properly. Here’s an example of the fixed code:

This change ensures that the admin variable is set to a valid address at the time of contract deployment, preventing potential access control issues and allowing for the intended functionality of the contract.

File Location

Adminable.sol