Summary: This report addresses a vulnerability in the tokenURI function of the FlowNFTDescriptor contract due to inadequate input validation. The lack of proper checks allows invalid data to be processed, potentially leading to security risks such as denial of service or unauthorized access.

Vulnerability Details: Affected Function: ** **tokenURI(address streamContract, uint256 tokenId)

The tokenURI function is designed to generate a URI that represents a specific token based on the provided streamContract address and tokenId. However, the function lacks sufficient input validation to ensure that these parameters are valid before processing them. Specifically, it does not check if the streamContract address is a valid contract address or if the tokenId corresponds to an existing token. You can ceck by running this foundry test:

The test in question confirms the following:

1. Lack of Input Validation: The test specifically checks whether the tokenURI function can generate a valid URI when an invalid contract address is passed as an argument. It highlights the absence of checks for input validity by confirming that the function does not revert when provided with a zero address for the streamContract. This behavior demonstrates that the function lacks necessary validations to ensure that the inputs meet expected criteria.

2. Functionality Under Invalid Conditions: The test successfully runs and generates a URI despite using an invalid streamContract address. This indicates that the function is designed to execute without proper error handling for invalid inputs, which could lead to the creation of misleading or incorrect data.

3. Potential Vulnerability Exposure: By confirming that the function executes successfully without reverting for invalid inputs, the test exposes a potential vulnerability that could be exploited by malicious actors. This lack of input validation could lead to scenarios where incorrect or unauthorized data is returned, impacting the integrity and reliability of the contract.

Impact: The lack of parameter validation in the contract poses several significant risks:

1. Incorrect Data Retrieval: Invalid inputs can lead to misleading or erroneous data being returned, which may confuse users or other contracts relying on accurate information.

2. Exploitation Risk: Attackers could manipulate the contract's behavior by providing invalid inputs, potentially accessing unauthorized data or functionalities.

3. Increased Gas Costs: Invalid inputs can lead to unnecessary computations, raising gas costs for users interacting with the contract.

4. Future Security Vulnerabilities: The absence of input validation could create a foundation for additional security issues in the future, especially if the contract evolves or integrates with other systems.

Recommendations: The following mitigation strategies should be implemented:

1. Input Validation:

   • Implement strict input validation checks in functions to ensure that parameters conform to expected formats, ranges, or types before processing. For example, checking if addresses are non-zero and if numerical inputs fall within expected limits.

2. Require Statements:

   • Use require statements to enforce preconditions for function parameters. For instance, you can check if an address is not zero or if a token ID is within a valid range, causing the transaction to revert if the conditions are not met.

3. Error Handling:

   • Define custom error messages for require statements to provide clearer feedback on why a transaction failed. This can help developers and users identify and correct input issues more easily.