CVE-2022-32923: Addressing a Correctness Issue in the JIT with Improved Checks

A critical security vulnerability, designated as CVE-2022-32923, has been identified and patched in the JIT (Just-In-Time) compiler used in various Apple operating systems and Safari Browser. The issue lies in a correctness problem in the JIT compiler and could result in the disclosure of internal application states if an attacker crafts malicious web content. This long-read post will discuss the details of the vulnerability, including code snippets, links to relevant references, and an explanation of the exploit.

Security Impact

An attacker who successfully exploits this vulnerability can potentially access sensitive information such as memory addresses or user data, which may lead to a further elevation of privileges or unauthorized access to other systems. However, Apple has already addressed this issue in the latest updates: tvOS 16.1, iOS 15.7.1 and iPadOS 15.7.1, macOS Ventura 13, watchOS 9.1, Safari 16.1, iOS 16.1, and iPadOS 16.1.

Exploit Details

The CVE-2022-32923 security vulnerability is triggered when the JIT compiler is presented with crafted web content that takes advantage of the correctness issue. The exploit leverages a lack of proper checks in the JIT compiler's implementation to coax it into revealing internal application states, which could lead to information disclosure.

Code Snippet

The exact code snippet for the exploit is not publicly available due to its sensitive nature, but let's take a look at a high-level representation of the JIT compiling process, which is where the vulnerability lies:

void jit_compile(JIT_Compiler *jit, Function *func) {
  // ... (code omitted for brevity)

  // Lacking proper checks here
  for (Instruction &inst : func->instructions) {
    // ... (code omitted for brevity)

    // Compiling instructions, potentially revealing internal app states
    compile_instruction(jit, inst);

    // ... (code omitted for brevity)
  }

  // ... (code omitted for brevity)
}

In this example, the jit_compile function compiles a given set of instructions. The vulnerability can be exploited via a lack of proper checks before executing the potentially malicious input.

iOS 16.1 and iPadOS 16.1

Users are highly encouraged to update their systems and applications to the latest available versions to protect against the potential exploitation of CVE-2022-32923.

For more information about the CVE-2022-32923 vulnerability, please refer to the following resources

1. Apple Security Updates: https://support.apple.com/en-us/HT201222
2. CVE Details: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32923
3. National Vulnerability Database: https://nvd.nist.gov/vuln/detail/CVE-2022-32923

Conclusion

The CVE-2022-32923 vulnerability highlights the importance of secure coding practices and thorough security review processes. It serves as a reminder for developers to implement appropriate checks and validation of input data to prevent potential exploits. For users, this incident underscores the need to stay up-to-date with software updates and maintain awareness of potential threats.

Timeline

Published on: 11/01/2022 20:15:00 UTC
Last modified on: 01/09/2023 16:44:00 UTC