CVE-2021-24045 : What You Need to Know

A type confusion vulnerability in Facebook Hermes prior to v0.10.0 could be exploited under specific conditions. Learn more about the impact, technical details, and mitigation steps.

Understanding CVE-2021-24045

This CVE highlights a type confusion vulnerability in Facebook Hermes, which could lead to security risks for applications using this technology.

What is CVE-2021-24045?

CVE-2021-24045 refers to a type confusion flaw that arises when resolving the "typeof" unary operator in Facebook Hermes versions earlier than v0.10.0. It is important to note that exploitation is dependent on whether the application allows the evaluation of untrusted JavaScript.

The Impact of CVE-2021-24045

The vulnerability could potentially be leveraged by malicious actors to execute arbitrary code, leading to remote code execution and other security breaches. However, most React Native applications are not affected by this issue.

Technical Details of CVE-2021-24045

Understanding the specifics of the vulnerability including its description, affected systems, and exploitation mechanism is crucial.

Vulnerability Description

The vulnerability is categorized under CWE-843, denoting the access of resources using an incompatible type, specifically 'Type Confusion'. This indicates a critical flaw in the handling of data types within Hermes.

Affected Systems and Versions

Facebook Hermes versions prior to v0.10.0 are susceptible to this vulnerability. Applications that permit the execution of untrusted JavaScript are at risk, emphasizing the importance of upgrading to the latest version.

Exploitation Mechanism

By exploiting the type confusion issue when resolving the "typeof" unary operator, attackers can bypass security mechanisms and execute arbitrary code within the affected applications.

Mitigation and Prevention

Taking immediate steps to address the vulnerability and adopting long-term security practices are essential to enhance system defenses.

Immediate Steps to Take

Developers and organizations should update to Facebook Hermes v0.10.0 or above to mitigate the risk of exploitation. Additionally, ensure that applications restrict the evaluation of untrusted JavaScript to avoid potential attacks.

Long-Term Security Practices

Implementing secure coding practices, conducting regular security assessments, and monitoring for any signs of unauthorized activities can bolster the overall security posture.

Patching and Updates

Stay informed about security advisories and updates released by Facebook for Hermes. Promptly apply patches and fixes to safeguard against known vulnerabilities and enhance the resilience of your applications.