CVE-2021-24037 : Vulnerability Insights and Analysis

A detailed overview of CVE-2021-24037, a use after free vulnerability in Hermes affecting certain versions of the product developed by Facebook.

Understanding CVE-2021-24037

This section will cover the description, impact, technical details, and mitigation strategies related to the CVE-2021-24037 vulnerability.

What is CVE-2021-24037?

CVE-2021-24037 is a use after free vulnerability in Hermes, a JavaScript engine developed by Facebook. The vulnerability arises while emitting specific error messages, allowing attackers to potentially execute arbitrary code via crafted JavaScript. It is important to note that this vulnerability is exploitable only if the application using Hermes allows the evaluation of untrusted JavaScript. Most React Native applications are not affected by this issue.

The Impact of CVE-2021-24037

The impact of this vulnerability is severe as it enables attackers to execute arbitrary code on affected systems. By exploiting this vulnerability, threat actors can compromise the security and integrity of the application and its data.

Technical Details of CVE-2021-24037

Let's delve into the technical aspects of CVE-2021-24037 to understand the vulnerability better.

Vulnerability Description

This vulnerability is classified as a use after free bug (CWE-416), which occurs in Hermes prior to the commit identified as 'd86e185e485b6330216dee8e854455c694e3a36e'. The flaw allows attackers to manipulate the memory of the application, potentially leading to arbitrary code execution.

Affected Systems and Versions

Hermes versions prior to the commit 'd86e185e485b6330216dee8e854455c694e3a36e' are affected by this vulnerability. Applications that permit the evaluation of untrusted JavaScript while using Hermes are at risk.

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting malicious JavaScript code and triggering the use after free condition in Hermes. This could allow them to execute arbitrary code on the target system.

Mitigation and Prevention

In this section, we will discuss the steps that can be taken to mitigate the risks associated with CVE-2021-24037.

Immediate Steps to Take

It is recommended to update Hermes to the latest version that includes the fix for the use after free vulnerability. Additionally, ensure that the application does not allow the evaluation of untrusted JavaScript to prevent exploitation.

Long-Term Security Practices

Implement secure coding practices and conduct regular security audits to identify and address vulnerabilities in the application's codebase. Training developers on secure coding techniques can also help prevent such issues in the future.

Patching and Updates

Stay informed about security advisories from Facebook and apply patches promptly. Regularly updating Hermes and enforcing secure configurations can help in maintaining a robust security posture.