CVE-2021-31616 Explained : Impact and Mitigation

Insufficient length checks in the ShapeShift KeepKey hardware wallet firmware before version 7.1.0 have led to a stack buffer overflow vulnerability. This CVE allows attackers to trigger a stack buffer overflow via crafted messages, potentially resulting in code execution by exploiting ethereum_extractThorchainSwapData(). The affected interface can be accessed remotely over WebUSB.

Understanding CVE-2021-31616

This section will delve deeper into the impact, technical details, and mitigation strategies related to CVE-2021-31616.

What is CVE-2021-31616?

The vulnerability in the ShapeShift KeepKey hardware wallet firmware prior to version 7.1.0 arises from inadequate length validations. By sending specially crafted messages, threat actors can exploit this weakness to trigger a stack buffer overflow, posing a risk of executing arbitrary code.

The Impact of CVE-2021-31616

The stack buffer overflow in ethereum_extractThorchainSwapData() within ethereum.c bypasses stack protections, paving the way for potential code execution. As the affected component is accessible remotely via WebUSB, the exploit can be triggered from a distance, increasing the severity of the vulnerability.

Technical Details of CVE-2021-31616

Let's explore the specifics of the vulnerability, including its description, affected systems, versions, and exploitation mechanism.

Vulnerability Description

The vulnerability allows threat actors to exploit insufficient length checks in the ShapeShift KeepKey hardware wallet firmware, pre 7.1.0, causing a stack buffer overflow. Through carefully crafted input, attackers can manipulate the ethereum_extractThorchainSwapData() function, evading stack protections and potentially achieving code execution.

Affected Systems and Versions

The impacted systems include ShapeShift KeepKey hardware wallets running firmware versions earlier than 7.1.0. Users with these versions are at risk of exploitation through the stack buffer overflow vulnerability.

Exploitation Mechanism

By sending crafted messages to the vulnerable ethereum_extractThorchainSwapData() function remotely over WebUSB, threat actors can trigger the stack buffer overflow. This overflow can then be leveraged to execute arbitrary code, compromising the integrity and security of the device.

Mitigation and Prevention

To address CVE-2021-31616, immediate steps along with long-term security practices and patching recommendations are crucial.

Immediate Steps to Take

Users of ShapeShift KeepKey hardware wallets should update their firmware to version 7.1.0 or later, which contains patches for the stack buffer overflow vulnerability. Additionally, users are advised to refrain from connecting their devices to untrusted or compromised systems to mitigate the risk of exploitation.

Long-Term Security Practices

Implementing robust secure coding practices, conducting regular security audits, and staying informed about firmware updates and security advisories are essential for bolstering the overall security posture of hardware wallets.

Patching and Updates

Regularly monitoring official sources like GitHub releases and security blogs for firmware patches and updates is vital. Promptly applying these patches to address known vulnerabilities like stack buffer overflows is crucial in maintaining the security of ShapeShift KeepKey hardware wallets.