Metamask Snap Audit Report for Kuna Labs

Management Summary

Kuna Labs contacted Sayfer Security in order to perform penetration testing on their MetaMask Snap in September 2023.

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

Over the research period of 2 weeks, no vulnerabilities were discovered in the system but 2 informational notes were added to the report.

In conclusion, the system’s security posture is competent.

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

getErrorMessage() Returns an Empty String

Description

getErrorMessage(), called by buildTransactionBlock() returns an empty string if the type and content of the object passed as a parameter are incorrect. This error is then propagated higher, resulting in no valuable information being added to the error message returned to the user that could help them identify the source of the problem.

● getErrorMessage(unknown)

function getErrorMessage(e: unknown): string {
 if (
   typeof e === 'object' &&
   e !== null &&
   'message' in e &&
   typeof e.message === 'string'
 ) {
   return e.message
 }
 return ''
}

Mitigation

We suggest returning an appropriate error depending on which element of the object is inconsistent with Snap’s assumptions.

signData() Will Soon Be Deprecated

Description

In line 98, signMessage() uses the function signData(Uint8Array), but if we go to the sources, we can find the following comment:

/**
* Return the signature for the data.
* Prefer the async version {@link sign}, as this method will be
deprecated in a future release.
*/

Therefore, sign(Uint8Array) from the same abstract class should be used instead.

Mitigation

Replace signData(Uint8Array) with sign(Uint8Array).

Appendix A: Security Evaluation Fixes

After a review by the Sayfer team, we certify that all the above-mentioned security issues have been addressed by the Kuna Labs team.

Sayfer certifies that there are no longer any major vulnerabilities in the Kuna Labs project that could cause security problems.

Fixes commit: 94df27dc82226aa8bd198f56a0317922a71f9cf9