Project

Summary

This vulnerability arises from inconsistently applied authorization checks across different functions in the contract, particularly in functions that rely on unprotected address inputs. An attacker could bypass these checks by passing crafted or unchecked addresses, allowing them to execute restricted actions such as unauthorized token minting, DAO membership changes, or fund transfers. If these authorization flaws are exploited, they could lead to a breakdown in access control, enabling unauthorized users to perform critical state changes within the contract.

Vulnerability Details

1. Inconsistent Authorization Checks: Authorization is inconsistently enforced in functions like joinDAO and upgradeTier, which rely on address-based checks but do not sufficiently validate or restrict certain inputs. This creates a scenario where an attacker could forge or bypass these checks with crafted addresses or insufficient permission verification.

2. Unchecked Address Inputs: Some functions in the contract accept addresses directly from user input without strict validation. If these addresses are left unchecked, attackers could pass manipulated values or call restricted functions via proxies, enabling access to privileged functions.

Link to the Affected Code

1. function joinDAO(address daoMembershipAddress, uint256 tierIndex) external

   • https://github.com/Cyfrin/2024-11-one-world/blob/1e872c7ab393c380010a507398d4b4caca1ae32b/contracts/dao/MembershipFactory.sol#L140-L150

2. function upgradeTier(address daoMembershipAddress, uint256 fromTierIndex) external

   • https://github.com/Cyfrin/2024-11-one-world/blob/1e872c7ab393c380010a507398d4b4caca1ae32b/contracts/dao/MembershipFactory.sol#L155-L161

Impact

The lack of consistent or sufficient authorization checks allows for unauthorized access to functions that perform state changes, mint/burn tokens, and transfer funds. By exploiting these gaps, an attacker could access or modify restricted functions without proper permissions, impacting membership integrity, fund security, and the intended governance structure.

Given the reliance on user-provided addresses without robust validation, there is a reasonable likelihood that an attacker could exploit this weakness. The impact of bypassing access control is severe, particularly for functions that involve state changes, membership validation, and fund transfers.

If an attacker successfully bypasses authorization, they could access restricted contract functions, leading to several possible exploit scenarios:

1. Unauthorized Memberships or Tier Upgrades: The attacker could forge their membership in a DAO or upgrade their tier without fulfilling required criteria, potentially impacting voting rights or privileges within the DAO.

2. Token Manipulation: By exploiting authorization flaws, an attacker could burn, mint, or transfer tokens in an unauthorized manner.

3. Fund Drains: Certain functions that transfer funds could be exploited to siphon assets from the contract or DAO treasury if unauthorized calls are allowed.

Attack Scenario

• Unauthorized users may gain high-tier membership or repeated token issuance without proper authorization, breaking the integrity of the membership structure.

• The DAO treasury may be drained by unauthorized transfers, affecting its financial stability and disrupting governance.

Proof of Concept

An attacker could execute the following proof-of-concept attack to gain unauthorized access:

1. Bypass Authorization with Unchecked Address Input: By providing a crafted address that matches a certain hash or expected pattern, the attacker could circumvent the authorization checks.

In this scenario, the attacker calls a restricted function with a crafted address, bypassing authorization checks.

Tools Used

Manual Review

Recommendations

1. Strictly Enforce Authorization Checks: Add restrictive modifiers on functions that manage funds, membership tiers, or sensitive state changes, ensuring only authorized users can access them.

2. Implement Access Control with RBAC: Use a role-based access control (RBAC) system like OpenZeppelin’s AccessControl to assign specific roles to users, reducing the risk of unauthorized access.

3. Add Input Validation for Address Fields: Apply address validation checks (e.g., checking for zero addresses, ensuring contract ownership) to prevent unauthorized calls.

By implementing these recommendations, the contract will enforce proper authorization consistently, ensuring only designated users can access and modify restricted functions.