CVE-2023-4576: Windows Integer Overflow in `RecordedSourceSurfaceCreation` leads to Heap Buffer Overflow and Potential Sandbox Escape

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Introduction

In the latest security bulletin, researchers have uncovered a new vulnerability in certain versions of Firefox on Windows systems, which can lead to a heap buffer overflow, potentially leaking sensitive data and paving a path to a harmful sandbox escape. This alarming issue was assigned the CVE identifier of CVE-2023-4576.

It is important to note that this vulnerability *only* impacts Windows users, so those using the Firefox browser on other operating systems, such as Linux or macOS, can rest assured that they are not affected by this particular bug.

Technical Details

The CVE-2023-4576 vulnerability specifically targets an integer overflow in the RecordedSourceSurfaceCreation function executed within the Windows operating system. This integer overflow can ultimately lead to a heap buffer overflow, which poses a significant risk to users as it can reveal sensitive information and potentially facilitate a sandbox escape.

Here is a code snippet that demonstrates how the integer overflow can occur

// Pseudo-code for RecordedSourceSurfaceCreation

int32_t width, height; // User-controlled values
int32_t byteSize;

byteSize = width * height * 4;  // Potential integer overflow

if (byteSize > MAX_SIZE) {
  return ERROR;
}

// Allocate memory for image data based on byteSize
uint8_t* imageData = (uint8_t*) malloc(byteSize); // Heap buffer overflow

The above code showcases how user-controlled values for

width

and

height

might cause an integer overflow while calculating the

byteSize

. This incorrect

byteSize

value can then lead to a heap buffer overflow, causing sensitive data leakage and potentially allowing attackers to trigger a sandbox escape.

Exploit Details

As of now, there have been no reported cases of this vulnerability being exploited in the wild. However, due to the sensitive nature of the information it could potentially expose—and the possibility of leading to a dangerous sandbox escape—it is highly recommended that affected users update their software to the latest version available immediately.

Check the original references for more information and up-to-date patches released by Mozilla

- Firefox Security Advisory: MFSA2023-22
- Thunderbird Security Advisory: MFSA2023-25
- CVE Details: CVE-2023-4576

Conclusion

CVE-2023-4576 is a critical integer overflow vulnerability affecting Windows users running vulnerable versions of Firefox and Thunderbird. Although there are no known cases where this bug has been exploited, it still possesses the potential to lead to a heap buffer overflow, compromising sensitive data and potentially facilitating a sandbox escape. Users running affected software are strongly advised to update their systems as soon as possible to stay protected.

Timeline

Published on: 09/11/2023 09:15:00 UTC
Last modified on: 09/13/2023 11:15:00 UTC