CVE-2023-42848: Heap Corruption Vulnerability in Image Processing Patched with Improved Bounds Checks

Security researchers have discovered a critical vulnerability, CVE-2023-42848, that affects multiple Apple platforms, including watchOS, macOS, tvOS, iOS, and iPadOS. By processing a maliciously crafted image, bad actors can exploit this vulnerability, leading to heap corruption. Fortunately, Apple has promptly addressed this issue with improved bounds checks, and all users are strongly advised to update their devices to the latest software versions. This post will delve into the details of the vulnerability, provide a code snippet illustrating the exploit, and share relevant reference links.

Exploit Details

The vulnerability, CVE-2023-42848, resides in the image processing mechanism across various Apple platforms. An attacker could craft a malicious image that, when processed, leads to heap corruption. This corruption may further enable bad actors to manipulate the program execution flow, often resulting in unauthorized access or control, crashes, or information leaks.

Affected platforms and versions include watchOS 10. and earlier, macOS Sonoma 14. and earlier, tvOS 17. and earlier, iOS 16.7.1 and earlier, and iPadOS 16.7.1 and earlier, as well as iOS 17. and iPadOS 17., and macOS Ventura 13.6. and earlier.

The vulnerability was fixed with improved bounds checks on watchOS 10.1, macOS Sonoma 14.1, tvOS 17.1, iOS 16.7.2 and iPadOS 16.7.2, iOS 17.1 and iPadOS 17.1, and macOS Ventura 13.6.1.

Code Snippet

Below is a simple code snippet illustrating a possible exploit scenario involving the processing of a maliciously crafted image.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// Function to simplify parsing a malicious image file
void process_image_file(const char* file_name) {
    // Read malicious image file
    FILE* file = fopen(file_name, "rb");

    if (! file) {
        printf("Error opening file: %s\n", file_name);
        return;
    }

    // Read file header: assume vulnerability in this header processing
    unsigned char header[64]; // May be variable in different image formats
    fread(header, sizeof(unsigned char), sizeof(header) / sizeof(unsigned char), file);

    // Vulnerability: no bounds checks while processing header
    int width = header[10]; // Index 10: just an example, indices may vary
    int height = header[20]; // Index 20: just an example, indices may vary

    // Heap corruption: possible attack vector
    unsigned char* image_data = (unsigned char*) malloc(width * height * sizeof(unsigned char));

    // Continue processing the file and then close it
    fclose(file);
}

int main() {
    const char* malicious_image = "path/to/malicious/image.file";
    process_image_file(malicious_image);

    return ;
}

Please note that this sample code is for illustration purposes only and does not represent actual vulnerable code.

Original References

1. CVE-2023-42848 - National Vulnerability Database (NVD)
2. Apple Security Updates
3. Apple Security Advisory

Conclusion

CVE-2023-42848 is a critical vulnerability affecting multiple Apple platforms, leading to heap corruption when processing maliciously crafted images. Users are urged to update their devices to the latest software versions containing the appropriate security patches. Keep your systems up-to-date to ensure protection against potential exploits related to this vulnerability.

Timeline

Published on: 02/21/2024 07:15:49 UTC
Last modified on: 02/22/2024 19:07:27 UTC