Metamask Snap Audit Report for AlephZero

Management Summary

AlephZero contacted Sayfer Security in order to perform penetration testing on AlephZero’s MetaMask Snap in November 2023.

Before assessing the above services, we held a kickoff meeting with the AlephZero technical team and received an overview of the system and the goals for this research.

Over the research period of 2 weeks, 5 vulnerabilities were found in the system. Also, some suggestions were added to the report for ongoing improvements.

Several fixes should be implemented following the report, but the system’s security posture is competent.

After a review by the Sayfer team, we certify that all the security issues mentioned in this report have been addressed by the AlephZero team.

Risk Methodology

At Sayfer, we are committed to delivering the highest quality penetration testing to our clients. That’s why we have implemented a comprehensive risk assessment model to evaluate the severity of our findings and provide our clients with the best possible recommendations for mitigation.

Our risk assessment model is based on two key factors: IMPACT and LIKELIHOOD. Impact refers to the potential harm that could result from an issue, such as financial loss, reputational damage, or a non-operational system. Likelihood refers to the probability that an issue will occur, taking into account factors such as the complexity of the attack and the number of potential attackers.

By combining these two factors, we can create a comprehensive understanding of the risk posed by a particular issue and provide our clients with a clear and actionable assessment of the severity of the issue. This approach allows us to prioritize our recommendations and ensure that our clients receive the best possible advice on how to protect their business.

Risk is defined as follows:

Security Evaluation Methodology

Sayfer uses OWASP WSTG as our technical standard when reviewing web applications. After gaining a thorough understanding of the system we decided which OWASP tests are required to evaluate the system.

Security Assessment

After understanding and defining the scope, performing threat modeling, and evaluating the correct tests required in order to fully check the application for security flaws, we performed our security assessment.

Issue Table Description

Issue title

Description

Here we provide a brief description of the issue and how it formed, the steps we made to find or exploit it, along with proof of concept (if present), and how this issue can affect the product or its users.

Mitigation

Suggested resolving options for this issue and links to advised sites for further remediation.

Security Assessment Findings

Lack of Validation in uint8ArrayFromHex(string)

Description

It has been found that uint8ArrayFromHex(string) does not validate whether the input hexString, which is of type string, is actually a hexadecimal.

• uint8ArrayFromHex(string):

export const uint8ArrayFromHex = (hexString: string) => {
const strBytes = hexString.replace(/^0x/iu, '').match(/../gu) ?? [];
return new Uint8Array(strBytes.map((byte: string) => parseInt(byte, 16)))
.buffer;
};

The function only replaces the “0x” characters with an empty string, as well as converting bytes to integers. Then, the buffer is returned as a uint8 string. Consequently, if such validation is not performed before calling the function, an incorrect string may be processed.

Mitigation

Validate that the function’s input is in fact a hexadecimal.

Type Checking Is not Uniform

Description

any type casting was sometimes used throughout the snap. This is considered a bad security practice, since it deprives us of important type information and may consequently lead to unexpected runtime errors when unexpected types are used.

Mitigation

When unsure about a type, they should be defined down using “unknown”, and then narrowed down by type guards.

Unused Functions

Description

While examining the code, we noticed that none of the functions in utils.ts are implemented anywhere in the codebase. The specified functions all have content, but are never called, making their presence in the code seemingly unnecessary.

This may be due to future code development, scrapping of certain functionalities, or a bug.

Mitigation

Make sure that the specified functions are necessary, and if they are, make sure to use them.

Dependency with Outstanding Vulnerability

Description

By running pnpm audit, we found out that one subdependency of your project, [email protected], is associated with a high risk vulnerability that may be relevant to your project.

Mitigation

Update @metamask/[email protected] as soon as possible and periodically run pnpm audit.

Lack of Documentation and Commenting

Description

The README file and several generic articles are the only materials describing the snap and its functionalities. Additionally, these articles do not match the code and function names that are implemented.

Mitigation

Write a proper readme and make sure to comment the code.