Prepared by:
HALBORN
Last Updated 12/19/2024
Date of Engagement: September 12th, 2024 - September 25th, 2024
Summary
100% of all REPORTED Findings have been addressed
All findings
3
Critical
0
High
1
Medium
2
Low
0
Informational
0
Table of Contents
1. Introduction
Fuelet engaged Halborn to conduct a security assessment of their Fuelet wallet Chrome extension, which began on September 12th, 2024 and ended on September 25th, 2024. The security assessment was scoped to the Fuelet wallet Chrome extension. The client team provided the source code to allow the security engineers to conduct testing using tools for scanning, detecting, and validating possible vulnerabilities, and report the findings at the end of the engagement.
2. Assessment Summary
The team at Halborn was provided a timeline for the engagement and assigned two full-time security engineers to verify the security of the assets in scope. The security engineers are penetration testing experts with advanced knowledge in web, mobile (Android and iOS), reconnaissance, blockchain and infrastructure penetration testing.
The goals of our security assessments are to improve the quality of the systems we review and to target sufficient remediation to help protect users.
During the security assessment, several vulnerabilities were identified that, while not critical, warrant attention to strengthen the application's overall security. Multiple valid account credentials were discovered in memory, highlighting an opportunity to enhance session management and secure storage practices. While the immediate risk of exploitation is limited, addressing this issue proactively will reduce the likelihood of unauthorized access or credential exposure. Additionally, the browser wallet does not lock upon instance closure, which, though not immediately critical, could lead to potential risks if user sessions are left unattended. Implementing proper wallet session isolation would improve user trust and mitigate potential security concerns.
Another observed issue was the persistence of sensitive information, such as passwords or keys, in the clipboard without automatic clearing mechanisms. Although this does not present an immediate threat, it may expose such data to interception if the system is compromised. Addressing these findings through secure coding practices and better session and memory management will help to mitigate risks while improving the application's security resilience over time.
For public release, this report was redacted per Fuelet request to exclude certain critical issues. It should be noted that all removed critical issues were fully addressed and resolved by the Fuelet team prior to the report's publication.
3. Test Approach and Methodology
Halborn followed a whitebox approach as per the scope and performed a combination of both manual and automated security testing to balance efficiency, timeliness, practicality, and accuracy regarding the scope of the pentest. While manual testing is recommended to uncover flaws in logic, process and implementation; automated testing techniques assist enhance coverage of the infrastructure and can quickly identify flaws in it.
The assessment methodology covered a range of phases of tests, and employed various tools, including but not limited to the following:
Verify minimum necessary permissions
Source code review
Hardcoded credentials or API keys
Sensitive data leakage
Robust Content Security Policy (CSP)
Manifest file configuration review
Validate and sanitize user inputs
Ensure sensitive data secure storage
Secure communications for all network communication
Security headers configuration
Ensure the least privileges for scripts
Component isolation verification
Third-party libraries review
Monitor extension behavior
Event listeners and handlers review
Data collection practices verification
Multiple browsers verification
Regulatory compliance
Static code analysis
Dynamic analysis
Review documentation completeness
4. RISK METHODOLOGY
- 5 - Almost certain an incident will occur.
- 4 - High probability of an incident occurring.
- 3 - Potential of a security incident in the long term.
- 2 - Low probability of an incident occurring.
- 1 - Very unlikely issue will cause an incident.
- 5 - May cause devastating and unrecoverable impact or loss.
- 4 - May cause a significant level of impact or loss.
- 3 - May cause a partial impact or loss to many.
- 2 - May cause temporary impact or loss.
- 1 - May cause minimal or un-noticeable impact.
- 10 - CRITICAL
- 9 - 8 - HIGH
- 7 - 6 - MEDIUM
- 5 - 4 - LOW
- 3 - 1 - VERY LOW AND INFORMATIONAL
5. SCOPE
6. Assessment Summary & Findings Overview
Critical
0
High
1
Medium
2
Low
0
Informational
0
Impact x Likelihood
HAL-01
HAL-02
HAL-03
| Security analysis | Risk level | Remediation Date |
|---|---|---|
| Multiple Valid Accounts Found in Memory | High | Solved - 10/15/2024 |
| Wallet Not Locked on Browser Instance Closing | Medium | Solved - 10/15/2024 |
| Sensitive Information Available in the Clipboard | Medium | Risk Accepted - 10/15/2024 |
7. Findings & Tech Details
7.1 Multiple Valid Accounts Found in Memory
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Description
In secure systems, private keys should only be available in memory for the shortest time necessary to perform cryptographic operations. If private keys are kept in memory for too long or are not properly cleared after use, they can be accessed by malicious actors through memory dumps, browser vulnerabilities, or malicious extensions. This poses a serious risk as an attacker can extract private keys from memory and use them to gain unauthorized access to accounts, sign transactions, or perform other critical actions on behalf of the user.
It was possible to retrieve the private key from the browser extension’s memory using basic memory inspection tools. If exploited, this could result in an attacker gaining unauthorized control of the user's accounts or assets.
Proof of Concept
Score
Recommendation
Limit the Time Keys Stay in Memory: Private keys should only be loaded into memory during the specific cryptographic operation (e.g., signing a transaction) and immediately wiped from memory afterward. This reduces the window of opportunity for an attacker to access the key.
Use Secure Storage for Private Keys: Private keys should be stored securely (e.g., encrypted storage) and only decrypted into memory when absolutely necessary. After the operation, securely overwrite the memory to prevent the private key from remaining accessible.
Use WebCrypto API: When working with cryptographic operations in a browser environment, use the WebCrypto API. This API is designed to perform cryptographic operations in a way that prevents sensitive data, like private keys, from being exposed in the browser’s memory.
Remediation
SOLVED: The wallet extension showed valid private keys in memory, even after finish the browser session.
However, after a discussion with the internal team, we agreed that the private keys present in memory were regarding that the private keys and the assetID contains the same formats. No private keys from the imported or generated accounts were found in memory.
7.2 Wallet Not Locked on Browser Instance Closing
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Description
The application is vulnerable due to the wallet remaining unlocked when the browser instance is closed. This security flaw occurs when a user’s wallet session persists even after the browser window or tab is closed, allowing the wallet to remain accessible without re-authentication upon reopening. This creates a critical security risk as it allows unauthorized access to the wallet, particularly in shared or public environments, or if the device is lost or compromised. This vulnerability undermines the security model that should protect sensitive user assets and private keys.
Proof of Concept
Execute an instance of the browser, open the wallet, close the browser instance and re-open to check that the wallet would remain unlocked
Score
Recommendation
Implement session management that automatically locks the wallet when the browser window or tab is closed. Require re-authentication (e.g., password, biometrics) when the user attempts to access the wallet again after a browser restart. Additionally, provide configurable timeout settings that automatically lock the wallet after a period of inactivity to further protect user assets. These measures will significantly enhance the security of the wallet and protect users against unauthorized access.
Remediation
SOLVED: The wallet extension locked correctly the wallet after session termination.
7.3 Sensitive Information Available in the Clipboard
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Description
The application allowed sensitive information, such as passwords, private keys, seed phrases, or personal data, to be copied to the clipboard without proper safeguards. When sensitive data is copied to the clipboard, it can be accessed by any other application running on the device, including malicious apps, keyloggers, or clipboard scrapers. This exposure creates a significant security risk, as clipboard data can be easily stolen or manipulated, leading to unauthorized access, data breaches, or identity theft.
The presence of sensitive information in the clipboard can lead to serious security consequences, including credential theft, account compromise, and financial loss. Attackers can monitor the clipboard to intercept copied data, allowing them to gain access to user accounts, wallets, or other protected resources. This vulnerability is particularly dangerous in shared or public devices, where clipboard data can persist beyond the intended session, inadvertently exposing private information to subsequent users or applications.
Proof of Concept
Score
Recommendation
Avoid copying sensitive information to the clipboard by default. Implement warnings or confirmation prompts when copying sensitive data is necessary, and consider automatically clearing the clipboard after a short interval or once the data is used.
Offer to the user the option to download the private key instead of using the clipboard functionality that can be accessed by a malicious crafted web application or third-party applications like terminal.
Remediation
RISK ACCEPTED: The Fuelet team accepted the risk of this finding.
Halborn strongly recommends conducting a follow-up assessment of the project either within six months or immediately following any material changes to the codebase, whichever comes first. This approach is crucial for maintaining the project’s integrity and addressing potential vulnerabilities introduced by code modifications.
Table of Contents
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