CVE-2023-4758: Understanding the Buffer Over-read Vulnerability Discovered in GitHub Repository gpac/gpac Prior to 2.3-DEV

In this extensive post, we are going to explore the details of a newly discovered vulnerability called CVE-2023-4758. This security flaw pertains to a buffer over-read issue found in the GitHub repository called gpac/gpac, specifically prior to its 2.3-DEV version. We will discuss important information such as the background of the repository, the vulnerability, code snippets, links to original references, and steps to exploit and mitigate this issue. Let's dive into the details and get a comprehensive understanding of CVE-2023-4758.

Background

The gpac/gpac repository on GitHub is an open-source project that provides multimedia tools and platforms primarily centered around the ISO Base Media File Format (ISO BMFF), also commonly known as the MP4 format. The repository consists of applications and libraries extensively used for various multimedia tasks such as encoding, streaming, and rendering. You can find the repository here: gpac/gpac GitHub Repository

Vulnerability Details (CVE-2023-4758)

CVE-2023-4758 is a buffer over-read vulnerability that exists in the gpac/gpac GitHub repository, specifically in the versions before 2.3-DEV. Buffer over-read occurs when a program reads memory beyond the actual size of the buffer, leading to potential information leaks or even crashes. In this case, the vulnerability resides in a particular function that mishandles buffer size calculations for some input data.

Code Snippet

Here's a simple code snippet that demonstrates the problematic code responsible for the buffer over-read issue:

void read_data_from_buffer(char* buffer, int buffer_size) {
    // ... some code here ...
    
    int read_size = get_data_size(buffer);

    // Issue: read_size may be greater than buffer_size, causing over-read.
    memcpy(destination, buffer, read_size);
}

In this code snippet, the memcpy() function is called with its source as the buffer and read_size as the number of bytes to copy. However, the read_size variable is obtained using the get_data_size() function, which may return a value larger than the actual buffer_size. As a result, the memcpy() function ends up reading beyond the buffer, hence causing a buffer over-read.

Here are some essential references for further reading and understanding

1. CVE-2023-4758: The official identifier page for the vulnerability by NIST: NIST CVE-2023-4758
2. gpac/gpac Repository: The official GitHub repository containing the problematic code: gpac/gpac GitHub Repository

Exploit Details

An attacker can exploit this vulnerability by specifically crafting an input file that, when processed by the affected application, would cause an over-read in the vulnerable function. By doing so, the attacker might gain access to sensitive information stored in the memory or cause a denial-of-service by crashing the application. It's essential to note that this vulnerability could be a building block for a more sophisticated attack, such as code execution or privilege escalation.

Mitigation

To mitigate the risk associated with CVE-2023-4758, users are advised to update their instances of gpac/gpac to version 2.3-DEV or later. This version includes a patch addressing the buffer over-read issue. In addition, developers should implement proper checks and validation to avoid potential buffer over-read concerns in their code.

Conclusion

In this extensive post, we have provided an insight into the buffer over-read vulnerability CVE-2023-4758 found in the GitHub repository gpac/gpac prior to 2.3-DEV. We have covered crucial information such as the background of the affected repository, exploit details, code snippets, and links to original references. Be sure to update your instances of gpac/gpac and follow best coding practices to avoid such vulnerabilities in the future. Stay safe and keep your software up to date!

Timeline

Published on: 09/04/2023 16:15:00 UTC
Last modified on: 09/06/2023 20:43:00 UTC