Understanding CVE-2023-27968: A Buffer Overflow Issue Addressed in macOS Ventura 13.3

Buffer overflow vulnerabilities often cause significant security risks as they can lead to unexpected system termination or allow malicious writes to kernel memory. Recently, a new buffer overflow vulnerability identified as CVE-2023-27968 was discovered and addressed in macOS Ventura 13.3. In this post, we will examine this vulnerability, discuss its implications, and analyze the associated code snippet while providing links to original references and exploit details.

Vulnerability Details (CVE-2023-27968)

CVE-2023-27968 refers to a critical security vulnerability in macOS Ventura. The exploit involves a buffer overflow issue that has been addressed with improved memory handling. As a result, this issue has been fixed in macOS Ventura 13.3. The vulnerability is rooted in a weakness within an app's code, which may enable the app to cause unexpected system termination or permit kernel memory writes. The potential impact of this exploit could be significant, as it could lead to a compromised system or unauthorized access to sensitive data.

Code Snippet

To better understand the code involved in this vulnerability, let's consider a simplified snippet of vulnerable code:

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

void vulnerable_function(char *input) {
    char buffer[100];  // Buffer with fixed size of 100 bytes
    strcpy(buffer, input);  // Copying user input to the buffer
}

int main(int argc, char **argv) {
    if (argc != 2) {
        printf("Usage: %s <input>\n", argv[]);
        return 1;
    }

    vulnerable_function(argv[1]);  // Passing user input to the vulnerable_function

    return ;
}

In this example, the vulnerable_function utilizes a fixed-size buffer to store user input. The function does not check the size of user input, which may lead to an overflow if the input is larger than the available buffer. By fixing the memory handling in this code, we can prevent the buffer overflow vulnerability from being exploited:

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

void fixed_function(char *input) {
    char buffer[100];  // Buffer with fixed size of 100 bytes
    strncpy(buffer, input, sizeof(buffer) - 1);  // Copying user input to the buffer with size check
    buffer[sizeof(buffer) - 1] = '\';  // Terminate the string with NULL character
}

int main(int argc, char **argv) {
    if (argc != 2) {
        printf("Usage: %s <input>\n", argv[]);
        return 1;
    }

    fixed_function(argv[1]);  // Passing user input to the fixed_function

    return ;
}

Here, the strncpy function is used instead of strcpy, ensuring that the input copied to the buffer does not exceed its size. Additionally, the buffer is explicitly terminated with a NULL character to eliminate the risk of overflow.

To read more about the CVE-2023-27968 vulnerability, you can consult the following sources

1. Apple Security Updates - macOS Ventura 13.3
2. CVE-2023-27968 - National Vulnerability Database (NVD)
3. MITRE CVE Dictionary Entry - CVE-2023-27968

Conclusion

The discovery and subsequent resolution of CVE-2023-27968 emphasize the importance of timely software updates and rigorous memory handling practices. By understanding this vulnerability and exercising proactive security measures, developers can prevent unpredictable consequences and protect their users' systems from potential harm.

Timeline

Published on: 05/08/2023 20:15:00 UTC
Last modified on: 05/12/2023 19:47:00 UTC