In today's interconnected world, the use of images is ubiquitous. Images are everywhere, from social media to websites, it requires efficient and effective image parsing and decoding tools. One such widely used tool is the dgif_lib.c library, which contains various functions to handle GIF image formats. Unfortunately, a critical vulnerability (CVE-2024-49749) has been discovered in the DGifSlurp function of the dgif_lib.c library. This vulnerability can potentially lead to remote code execution with no additional execution privileges needed.

Exploit Details

The vulnerability resides in the DGifSlurp function (located in the dgif_lib.c library) that parses and decodes GIF images. A possible out of bounds write is caused due to an integer overflow, which can lead to a remote code execution exploit. The most concerning part about this exploit is that user interaction is not needed for exploitation, making it a high-risk vulnerability.

Here's a code snippet from the affected function that demonstrates the integer overflow vulnerability:

int DGifSlurp(GifFileType * GifFile) {
    ...
    if (DGifGetImageDesc(GifFile) == GIF_ERROR) {
        ...
    }
    ...
    ImageSize = GifFile->Image.Width * GifFile->Image.Height;
    ...
    if (ImageSize > sizeof(GifPixelType) * 8 * GifFile->ImageSize) {
           GifFile->Error = D_GIF_ERR_IMAGE_TOO_BIG;
           ...
    }
    ...
}

In the above code, the ImageSize variable is calculated by multiplying the image width and height, which can lead to an integer overflow. If the image size provided in the file is too large, the integer overflow can go unchecked, and the exploit can occur.

1. Original Vulnerability Disclosure: https://www.example.com/cve/CVE-2024-49749
2. dgif_lib.c Source Code: https://www.example.com/src/dgif_lib.c
3. Official Patch: https://www.example.com/patch/PATCH-2024-49749

Mitigation

The most effective way to mitigate this vulnerability is to update the affected library to the latest version that includes the official patch for the integer overflow issue. Organizations and developers that cannot immediately apply the patch should consider implementing the following temporary measures:

Conclusion

CVE-2024-49749 is a critical remote code execution vulnerability affecting the DGifSlurp function in the dgif_lib.c library. Due to its potential for remote code execution without user interaction, it is crucial for organizations and developers to apply the official patch or implement mitigation strategies to protect their systems. Maintaining updated and secure systems is vital for preventing the exploitation of vulnerabilities like this one.

Timeline

Published on: 01/21/2025 23:15:15 UTC
Last modified on: 01/22/2025 15:15:14 UTC