CVE-2019-11839 : Exploit Details and Defense Strategies

Version 0.3.1 of the njs JavaScript engine, utilized in NGINX, contains a vulnerability in the Array.prototype.push function leading to a heap-based buffer overflow. This issue is specifically associated with the njs_array_prototype_push function in the njs_array.c file due to mishandling of size during the njs_array_expand process.

Understanding CVE-2019-11839

This CVE identifies a heap-based buffer overflow vulnerability in njs 0.3.1 used in NGINX.

What is CVE-2019-11839?

CVE-2019-11839 is a vulnerability in the njs JavaScript engine version 0.3.1, commonly employed in NGINX, leading to a heap-based buffer overflow.

The Impact of CVE-2019-11839

The vulnerability can be exploited to trigger a heap-based buffer overflow, potentially leading to arbitrary code execution or denial of service.

Technical Details of CVE-2019-11839

The technical aspects of this CVE are as follows:

Vulnerability Description

The vulnerability exists in the Array.prototype.push function of njs 0.3.1, specifically in the njs_array_prototype_push function in the njs_array.c file.

Affected Systems and Versions

Product: n/a
Vendor: n/a
Versions: n/a

Exploitation Mechanism

The vulnerability occurs after a resize operation, where the mishandling of size during the njs_array_expand process triggers the heap-based buffer overflow.

Mitigation and Prevention

To address CVE-2019-11839, consider the following steps:

Immediate Steps to Take

Update NGINX to a patched version that addresses the vulnerability.
Monitor vendor communications for security advisories and patches.

Long-Term Security Practices

Regularly update software and components to the latest versions.
Implement secure coding practices to prevent buffer overflows and other vulnerabilities.

Patching and Updates

Apply patches provided by NGINX promptly to mitigate the vulnerability and enhance system security.