Metamask Snap Audit Report for Sei
Management Summary
Sei contacted Sayfer Security in order to perform penetration testing on Sei’s MetaMask Snap in January 2024.
Before assessing the above services, we held a kickoff meeting with the Sei technical team and received an overview of the system and the goals for this research.
Over the research period of 2 weeks, we discovered 3 vulnerabilities in the system.
In conclusion, 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 Sei 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:
Vulnerabilities by Risk
High – Direct threat to key business processes.
Medium – Indirect threat to key business processes or partial threat to business processes.
Low – No direct threat exists. The vulnerability may be exploited using other vulnerabilities.
Informational – This finding does not indicate vulnerability, but states a comment that notifies about design flaws and improper implementation that might cause a problem in the long run.
Approach
Introduction
Sei contacted Sayfer to perform penetration testing on their MetaMask Snap application.
This report documents the research carried out by Sayfer targeting the selected resources defined under the research scope. Particularly, this report displays the security posture review for Sei’s MetaMask Snap application and its surrounding infrastructure and process implementations.
Our penetration testing project life cycle:
Scope Overview
Technical Overview
Scope Validation
Threat Model
Security Evaluation
Security Assessment
Scope Validation
We began by ensuring that the scope defined to us by the client was technically logical.
Deciding what scope is right for a given system is part of the initial discussion. Getting the scope right is key to deriving maximum business value from the research.
Threat Model
During our kickoff meetings with the client we defined the most important assets the application possesses.
We defined that the largest current threat to the system is the ability of malicious actors to steal funds from other users.
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
| ID | SAY-??: An ID for easy communication on each vulnerability |
| Status | Open/Fixed/Acknowledged |
| Risk | Represents the risk factor of the issue. For further description refer to the Vulnerabilities by Risk section. |
| Business Impact | The main risk of the vulnerability at a business level. |
| Location | The URL or the file in which this issue was detected. Issues with no location have no particular location and refer to the product as a whole. |
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 Evaluation
The following tests were conducted while auditing the system
Information Gathering
| Information Gathering | Test Name |
| WSTG-INFO-01 | Conduct Search Engine Discovery Reconnaissance for Information Leakage |
| WSTG-INFO-02 | Fingerprint Web Server |
| WSTG-INFO-03 | Review Webserver Metafiles for Information Leakage |
| WSTG-INFO-04 | Enumerate Applications on Webserver |
| WSTG-INFO-05 | Review Webpage Content for Information Leakage |
| WSTG-INFO-06 | Identify application entry points |
| WSTG-INFO-07 | Map execution paths through application |
| WSTG-INFO-08 | Fingerprint Web Application Framework |
| WSTG-INFO-09 | Fingerprint Web Application |
| WSTG-INFO-10 | Map Application Architecture |
Configuration and Deploy Management Testing
| Configuration and Deploy Management Testing | Test Name |
| WSTG-CONF-01 | Test Network Infrastructure Configuration |
| WSTG-CONF-02 | Test Application Platform Configuration |
| WSTG-CONF-03 | Test File Extensions Handling for Sensitive Information |
| WSTG-CONF-04 | Review Old Backup and Unreferenced Files for Sensitive Information |
| WSTG-CONF-05 | Enumerate Infrastructure and Application Admin Interfaces |
| WSTG-CONF-06 | Test HTTP Methods |
| WSTG-CONF-07 | Test HTTP Strict Transport Security |
| WSTG-CONF-08 | Test RIA cross domain policy |
| WSTG-CONF-09 | Test File Permission |
| WSTG-CONF-10 | Test for Subdomain Takeover |
| WSTG-CONF-11 | Test Cloud Storage |
Identity Management Testing
| Identity Management Testing | Test Name |
| WSTG-IDNT-01 | Test Role Definitions |
| WSTG-IDNT-02 | Test User Registration Process |
| WSTG-IDNT-03 | Test Account Provisioning Process |
| WSTG-IDNT-04 | Testing for Account Enumeration and Guessable User Account |
| WSTG-IDNT-05 | Testing for Weak or unenforced username policy |
Authentication Testing
| Authentication Testing | Test Name |
| WSTG-ATHN-01 | Testing for Credentials Transported over an Encrypted Channel |
| WSTG-ATHN-02 | Testing for Default Credentials |
| WSTG-ATHN-03 | Testing for Weak Lock Out Mechanism |
| WSTG-ATHN-04 | Testing for Bypassing Authentication Schema |
| WSTG-ATHN-05 | Testing for Vulnerable Remember Password |
| WSTG-ATHN-06 | Testing for Browser Cache Weaknesses |
| WSTG-ATHN-07 | Testing for Weak Password Policy |
| WSTG-ATHN-08 | Testing for Weak Security Question Answer |
| WSTG-ATHN-09 | Testing for Weak Password Change or Reset Functionalities |
| WSTG-ATHN-10 | Testing for Weaker Authentication in Alternative Channel |
Authorization Testing
| Authorization Testing | Test Name |
| WSTG-ATHZ-01 | Testing Directory Traversal File Include |
| WSTG-ATHZ-02 | Testing for Bypassing Authorization Schema |
| WSTG-ATHZ-03 | Testing for Privilege Escalation |
| WSTG-ATHZ-04 | Testing for Insecure Direct Object References |
Session Management Testing
| Session Management Testing | Test Name |
| WSTG-SESS-01 | Testing for Session Management Schema |
| WSTG-SESS-02 | Testing for Cookies Attributes |
| WSTG-SESS-03 | Testing for Session Fixation |
| WSTG-SESS-04 | Testing for Exposed Session Variables |
| WSTG-SESS-05 | Testing for Cross Site Request Forgery |
| WSTG-SESS-06 | Testing for Logout Functionality |
| WSTG-SESS-07 | Testing Session Timeout |
| WSTG-SESS-08 | Testing for Session Puzzling |
| WSTG-SESS-09 | Testing for Session Hijacking |
Data Validation Testing
| Data Validation Testing | Test Name |
| WSTG-INPV-01 | Testing for Reflected Cross Site Scripting |
| WSTG-INPV-02 | Testing for Stored Cross Site Scripting |
| WSTG-INPV-03 | Testing for HTTP Verb Tampering |
| WSTG-INPV-04 | Testing for HTTP Parameter Pollution |
| WSTG-INPV-05 | Testing for SQL Injection |
| WSTG-INPV-06 | Testing for LDAP Injection |
| WSTG-INPV-07 | Testing for XML Injection |
| WSTG-INPV-08 | Testing for SSI Injection |
| WSTG-INPV-09 | Testing for XPath Injection |
| WSTG-INPV-10 | Testing for IMAP SMTP Injection |
| WSTG-INPV-11 | Testing for Code Injection |
| WSTG-INPV-12 | Testing for Command Injection |
| WSTG-INPV-13 | Testing for Format String Injection |
| WSTG-INPV-14 | Testing for Incubated Vulnerability |
| WSTG-INPV-15 | Testing for HTTP Splitting Smuggling |
| WSTG-INPV-16 | Testing for HTTP Incoming Requests |
| WSTG-INPV-17 | Testing for Host Header Injection |
| WSTG-INPV-18 | Testing for Server-side Template Injection |
| WSTG-INPV-19 | Testing for Server-Side Request Forgery |
Error Handling
| Error Handling | Test Name |
| WSTG-ERRH-01 | Testing for Improper Error Handling |
| WSTG-ERRH-02 | Testing for Stack Traces |
Cryptography
| Cryptography | Test Name |
| WSTG-CRYP-01 | Testing for Weak Transport Layer Security |
| WSTG-CRYP-02 | Testing for Padding Oracle |
| WSTG-CRYP-03 | Testing for Sensitive Information Sent via Unencrypted Channels |
| WSTG-CRYP-04 | Testing for Weak Encryption |
Business logic Testing
| Business logic Testing | Test Name |
| WSTG-BUSL-01 | Test Business Logic Data Validation |
| WSTG-BUSL-02 | Test Ability to Forge Requests |
| WSTG-BUSL-03 | Test Integrity Checks |
| WSTG-BUSL-04 | Test for Process Timing |
| WSTG-BUSL-05 | Test Number of Times a Function Can be Used Limits |
| WSTG-BUSL-06 | Testing for the Circumvention of Work Flows |
| WSTG-BUSL-07 | Test Defenses Against Application Mis-use |
| WSTG-BUSL-08 | Test Upload of Unexpected File Types |
| WSTG-BUSL-09 | Test Upload of Malicious Files |
Client Side Testing
| Client Side Testing | Test Name |
| WSTG-CLNT-01 | Testing for DOM-Based Cross Site Scripting |
| WSTG-CLNT-02 | Testing for JavaScript Execution |
| WSTG-CLNT-03 | Testing for HTML Injection |
| WSTG-CLNT-04 | Testing for Client Side URL Redirect |
| WSTG-CLNT-05 | Testing for CSS Injection |
| WSTG-CLNT-06 | Testing for Client Side Resource Manipulation |
| WSTG-CLNT-07 | Test Cross Origin Resource Sharing |
| WSTG-CLNT-08 | Testing for Cross Site Flashing |
| WSTG-CLNT-09 | Testing for Clickjacking |
| WSTG-CLNT-10 | Testing WebSockets |
| WSTG-CLNT-11 | Test Web Messaging |
| WSTG-CLNT-12 | Testing Browser Storage |
| WSTG-CLNT-13 | Testing for Cross Site Script Inclusion |
API Testing
| API Testing | Test Name |
| WSTG-APIT-01 | Testing GraphQL |
Order audit from Sayfer
Security Assessment Findings
[L] Functions Return on Failure without Throwing an Error
| ID | SAY-01 |
| Status | Fixed |
| Risk | Low |
| Business Impact | If an error occurs, the program will end silently. This can be troublesome for users who, if the dApp does not personally handle it, will not receive a specific error description. |
| Location | – src/api.ts:30, 65 |
Description
When calling the signDirect and signAmino handlers, if account or account.privateKey do not exist, the program terminates without returning an error message. While this does not pose a threat from a security perspective, the user will not receive any useful feedback explaining why the snap failed.
- src/api.ts:30, 65
if (!account?.privateKey) return;Mitigation
When the program fails, it should always return an error message and display it to the user.
[I] Unused Function
| ID | SAY-02 |
| Status | Fixed |
| Risk | Informational |
| Business Impact | This finding does not have any effect on the snap’s functionality or usability. It was therefore classified as informational. |
| Location | – src/snapWallet.ts:80; getWallet(number, string) |
Description
The getWallet function in snapWallet.ts is not called by any RPC handler defined in the snap. Additionally, an identical function with the same content already exists in the core package.
Mitigation
The existence of this duplicated method does not seem to serve any functionality. It can be safely removed.
[I] Missing Documentation
| ID | SAY-03 |
| Status | Fixed |
| Risk | Informational |
| Business Impact | The lack of documentation can be a hindrance for users and developers creating Snap-enabled dApps. It also makes it harder for auditors such as us to assess whether the code is meeting its design requirements and point out failure points. |
| Location | — |
Description
The snap does not appear to have any form of technical documentation explaining the individual RPC methods, their application, or the functional requirements that the code should meet. It is good practice to have a description of each entrypoint that is made available to users for use.
Mitigation
We suggest creating technical documentation indicating the description of each RPC handler, as well as describing the methods of communicating with them from the dApp level.