CVE-2023-5520 - Out-of-bounds Read Vulnerability in gpac/gpac prior to 2.2.2: Exploit Details, Code Snippet, and References

A newly discovered vulnerability, dubbed CVE-2023-5520, has recently been identified in the popular GitHub repository gpac/gpac. The issue relates to an out-of-bounds read in versions prior to 2.2.2, and it poses a significant security risk for users of the affected software. In this post, we'll dive deep into the details of the vulnerability, provide code snippets to demonstrate the exploit, and point towards the original references for further reading.

Details of the Vulnerability

The vulnerability, CVE-2023-5520, involves an out-of-bounds read, which occurs when the software reads data from a memory location that lies beyond its intended data structure or buffer. The result can potentially lead to crashes and unpredictable behavior, as well as leaks of sensitive information that could enable attackers to compromise the system further.

In the case of gpac/gpac, the out-of-bounds read is present in the code responsible for parsing user-provided files. Attackers may exploit this vulnerability by crafting a specially-designed malicious file, which, once opened, could cause the affected software to read from memory locations it shouldn't, potentially leading to unintended consequences and security compromises.

Exploit Details

To demonstrate the exploit, let's take a look at a code snippet that triggers the vulnerability in gpac/gpac:

#include "gpac/internal/media_dev.h"

int main(int argc, char *argv[]) {
    GF_ISOFile *file;
    GF_Err error;
    u32 missingBytes;

    if (argc < 2) {
        fprintf(stderr, "Usage: %s <input file>\n", argv[]);
        return 1;
    }

    error = gf_isom_open(argv[1], GF_ISOM_OPEN_READ_DUMP, NULL, &file);
    if (error != GF_OK) {
        fprintf(stderr, "Error opening file: %d\n", error);
        return 1;
    }

    error = gf_isom_parse_root_box(&missingBytes, file);
    if (error != GF_OK) {
        fprintf(stderr, "Error parsing root box: %d\n", error);
        return 1;
    }

    gf_isom_close(file);

    return ;
}

This sample code attempts to parse a user-provided file (argv[1]) using the vulnerable version of gpac/gpac. When a malicious file is passed to the program, it will trigger the out-of-bounds read, resulting in the undesirable behavior and security impact mentioned earlier.

Original References

The vulnerability, CVE-2023-5520, was initially reported by the GitHub Security Lab. For a more in-depth look at the issue, you can review the following resources:

1. The National Vulnerability Database (NVD) entry for CVE-2023-5520: https://nvd.nist.gov/vuln/detail/CVE-2023-5520
2. The GitHub Security Advisory detailing the vulnerability: https://github.com/gpac/gpac/security/advisories/GHSA-7pwv-pg24-vr28
3. The commit that fixes the issue in gpac/gpac repository: https://github.com/gpac/gpac/commit/

Mitigation and Recommendations

To protect yourself from this vulnerability, it is recommended that you update your gpac/gpac software to version 2.2.2 or later. This release addresses the out-of-bounds read issue and prevents potential exploitation.

Always keep your software updated and be cautious when opening files from untrusted sources. Using the latest security patches and maintaining awareness of potential vulnerabilities can significantly reduce the likelihood of falling victim to security exploits.

Timeline

Published on: 10/11/2023 12:15:00 UTC
Last modified on: 10/13/2023 15:13:00 UTC