CVE-2023-35993: Use-After-Free Issue Fix in macOS, iOS, iPadOS, tvOS, and watchOS, Addressing Kernel Privilege Exploitation

Several operating systems produced by Apple, such as macOS, iOS, and iPadOS, had been impacted by a use-after-free issue that could potentially allow an app to execute arbitrary code with kernel privileges. This vulnerability has been identified with the code CVE-2023-35993. To address this problem, Apple released updates for macOS Monterey, iOS, iPadOS, tvOS, macOS Big Sur, macOS Ventura, and watchOS. In this post, we'll explore the details of the use-after-free issue, the updates that fix the problem, and the potential risks involved before applying the security updates.

The Use-After-Free Issue

The use-after-free issue is a type of memory management vulnerability that arises when a program continues to use a pointer after it has been freed. This can lead to arbitrary code execution and potentially grant an attacker high-level access to the affected system. Ref

'''

include

int main() {
   int *ptr = malloc(sizeof(int)); // Allocate memory
   free(ptr); // Free memory
   *ptr = 42; // Use-after-free occurs here

return ;

}
'''

The above code snippet demonstrates how the use-after-free issue could be triggered. The memory is first allocated with malloc(), then immediately freed using free(). However, the program continues to use the ptr pointer by assigning a value to it, resulting in a use-after-free situation.

Apple has addressed this use-after-free issue in the following software versions

- macOS Monterey 12.6.8 Ref
- iOS 15.7.8 and iPadOS 15.7.8 Ref
- iOS 16.6 and iPadOS 16.6 Ref
- tvOS 16.6 Ref
- macOS Big Sur 11.7.9 Ref
- macOS Ventura 13.5 Ref
- watchOS 9.6 Ref

Users are encouraged to update their systems to the latest versions to mitigate the risk associated with this vulnerability.

Exploit Details

The use-after-free issue allows an app to execute arbitrary code with kernel privileges, potentially granting a malicious app the ability to bypass security measures, escalate privileges, or compromise sensitive data. Kernel privileges grant the highest level of access to a system, enabling an attacker to perform actions such as:

Launching, stopping, or altering the behavior of services and processes.

It is important to note that in order to exploit this vulnerability, malicious code would need to be introduced through an app, thus emphasizing the importance of good security practices such as only installing apps from trusted sources and keeping software up-to-date.

Conclusion

Apple has addressed the use-after-free issue identified as CVE-2023-35993 by implementing improved memory management in several of their operating systems. Users are advised to update their systems to the latest software versions to ensure that they are protected against potential exploitation. As with any security vulnerability, users should also practice good cybersecurity habits to further minimize the risks associated with this and other issues.

Timeline

Published on: 07/27/2023 01:15:32 UTC
Last modified on: 08/03/2023 17:01:05 UTC