Introduction: PHP is a widely-used scripting language for web development, powering many popular websites and applications across the globe. The PHP team works diligently to fix vulnerabilities and security issues in the language to ensure the safety of developers and users alike. In this post, we will discuss a recently unearthed security vulnerability, CVE-2023-3824, which affects certain versions of PHP. We will delve into its particulars, including a code snippet demonstrating the vulnerability, original references for further study, and exploit details that could be valuable for both attackers and defenders.

Vulnerability Details: The vulnerability exists in PHP version 8..* before 8..30, 8.1.* before 8.1.22, and 8.2.* before 8.2.8. Specifically, the issue lies in the process of loading a phar file. When reading PHAR directory entries, there is insufficient length checking, which may lead to a stack buffer overflow. Consequently, this could potentially result in memory corruption or remote code execution (RCE). Remote code execution vulnerabilities are highly critical, as they allow attackers to run arbitrary code on the targeted system, leading to full system compromise.

Code Snippet: Here is a simple code snippet that demonstrates how the vulnerable Phar::loadPhar() function could be used:


try {
    echo 'Phar loaded successfully.';
} catch (Exception $e) {
    echo 'Error loading Phar: ' . $e->getMessage();


In the example above, the Phar::loadPhar() function is called to load a phar file named 'example.phar'. Since PHP does not perform sufficient length checking when reading the PHAR directory entries, a maliciously crafted phar file could potentially exploit this vulnerability, causing a stack buffer overflow.

Original References: The PHP team has officially acknowledged this vulnerability and released security advisories to address the issue. They have provided patches for the affected PHP versions to prevent exploitation. The official advisories can be found at the following links:

- PHP 8..30 Release Announcement
- PHP 8.1.22 Release Announcement
- PHP 8.2.8 Release Announcement

Additionally, the full details of CVE-2023-3824 can be found at the National Vulnerability Database (NVD).

Exploit Details: As of now, there have been no public proof-of-concept exploits or known active attacks exploiting this vulnerability. However, considering the critical nature of RCE vulnerabilities, threat actors could potentially discover a method of exploiting the issue, making it vital for developers to apply the provided security patches promptly. It is recommended to keep PHP versions updated regularly to minimize exposure to any vulnerabilities.

Conclusion: The CVE-2023-3824 vulnerability poses a significant risk to PHP applications running on vulnerable versions. To protect against exploitation, developers should ensure they are running the patched PHP versions (8..30, 8.1.22, or 8.2.8) and keep an eye out for future security updates from the PHP team. The disclosure of this vulnerability highlights the importance of staying informed about security issues within the languages and technologies we use daily to build better, safer web experiences.


Published on: 08/11/2023 06:15:00 UTC
Last modified on: 08/25/2023 23:15:00 UTC