The Common Vulnerabilities and Exposures (CVE) system recently reported a memory corruption vulnerability identified as CVE-2023-27965. This vulnerability affects devices running macOS Ventura 13.3 and Studio Display firmware version 16.4. In this long read post, we will examine how this vulnerability was discovered, analyze the details of this exploit, and discuss the improvements made in state management to address this issue.

Memory Corruption Issue

Memory corruption occurs when a computer program modifies the memory content in an unexpected way, leading to unpredictable behavior, crashes, or other undesirable consequences. In the case of CVE-2023-27965, an attacker has found a way to exploit this vulnerability and execute arbitrary code with kernel privileges. This can result in unauthorized access to sensitive information, data tampering, or even full device control.

Original References

The vulnerability information was originally published by the MITRE Corporation, a federally funded research and development center, which is responsible for managing the CVE system. The following are some useful links to official sources:

- CVE-2023-27965: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-27965
- Apple Security: https://support.apple.com/en-us/HT212894

Exploit Details

The specific details of this exploit are not publicly disclosed to prevent malicious actors from taking advantage of it. However, it is important to understand that the vulnerability relies on exploiting memory corruption issues in the affected systems.

A hypothetical scenario of such an exploit could look like the following pseudocode

function corruptMemory(input) {
  var corruptedObj = {}
  var buffer = new ArrayBuffer(1024)

  for (var i = ; i < input.length; i++) {
    // Exploit memory corruption issue
    corruptedObj['memory'] = arbitraryData
  }

  return corruptedObj
}

function main() {
  var user = getUserInput()
  var corruptedMemory = corruptMemory(user)

  // Execute arbitrary code with kernel privileges
  executeKernelPrivileges(corruptedMemory)
}

main()

In this example, an attacker may send a malicious input that, when processed by the corruptMemory function, would exploit the memory corruption issue and create an object with arbitrary data. The main function would then use this corrupted object to execute code at a kernel level, potentially granting the attacker full control of the device.

Improved State Management

To address this memory corruption issue, Apple released Studio Display Firmware Update 16.4 for Studio Display devices and macOS Ventura 13.3 for Mac computers. These updates improved state management in the system, mitigating the vulnerability. With these changes, the system will more safely manage memory allocation and reduce the likelihood of memory corruption issues.

In a similar exploitation scenario as before, the improved state management would make it much harder for the attacker to exploit the vulnerability:

function improvedMemoryManagement(input) {
  var protectedObj = {}
  var buffer = new SecureArrayBuffer(1024)

  for (var i = ; i < input.length; i++) {
    // Safely update memory content
    protectedObj['memory'] = safelyUpdateData(input)
  }

  return protectedObj
}

function main() {
  var user = getUserInput()
  var protectedMemory = improvedMemoryManagement(user)

  // The system is now protected against the exploit
}

main()

Conclusion

CVE-2023-27965 highlights the importance of regularly reviewing and updating software and firmware to protect against potential vulnerabilities. By addressing this memory corruption issue with improved state management, Apple was able to mitigate the risk associated with this vulnerability. Users of affected devices should ensure they install the latest updates to keep their devices secure.

Timeline

Published on: 05/08/2023 20:15:00 UTC
Last modified on: 05/19/2023 16:15:00 UTC