In 2023, Apple fixed a significant security bug affecting macOS Ventura. The vulnerability, tracked as CVE-2023-32429, let a malicious app bypass Privacy preferences, allowing access to user data without proper permissions. While Apple quickly addressed the problem with improved checks in macOS Ventura 13.5, let’s break down how this flaw worked, how it could be exploited, and what the patch changed.

What is CVE-2023-32429?

CVE-2023-32429 is a security issue labeled as “an app may be able to bypass Privacy preferences” in Apple’s official release notes. Simply put: an app that you didn’t give explicit permission could tap into sensitive resources, potentially snooping into your files, camera, microphone, and more.

- Apple advisory: HT213820 - Apple security releases
- NVD entry: NVD - CVE-2023-32429

Why Does macOS Have Privacy Preferences?

Apple’s macOS asks users for permission when apps want to access things like Documents, Desktop, Camera, Microphone, or even your Calendar. These are called Privacy preferences.

Without these permissions, apps are blocked by Transparency, Consent, and Control (TCC), Apple’s privacy framework.

What Went Wrong?

In the vulnerable macOS versions (before Ventura 13.5), there were flaws in how the privacy checks were enforced. In some situations, a crafty app could trick or bypass these privacy controls. While Apple hasn’t published all technical details to prevent widespread abuse, security researchers believe the bug relates to missing or insufficient checks in Apple’s TCC daemon (tccd).

If denied, access is blocked.

CVE-2023-32429 occurred because Step 3, the system's check, was faulty. Malicious apps could sometimes skip Step 3, accessing protected resources anyway.

Exploit Details: How Could This Be Used?

*Note: The public exploits are limited, but we can describe how a proof-of-concept (PoC) attack might look.*

The app requests access to a protected resource (like your files or the camera).

- Instead of going through regular TCC checks, the app uses a known "bypass" trick, such as leveraging a bug or calling a system API incorrectly handled by TCC.

Code Snippet (Hypothetical)

Suppose the vulnerable macOS failed to check the com.apple.private.tcc.allow entitlement correctly. An attacker could craft code like this (Objective-C):

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // Try to access sensitive directory
        NSString *path = @"/Users/USERNAME/Documents/secret.txt";
        NSError *error = nil;
        NSString *contents = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:&error];
        if (error) {
            NSLog(@"Failed to read file: %@", error);
        } else {
            NSLog(@"File contents: %@", contents);
        }
    }
    return ;
}

On patched systems, this would fail without permission. On vulnerable systems, using the exploit, access would unexpectedly succeed.

Apple’s Fix: Improved Checks

In macOS Ventura 13.5, Apple fixed the bug by tightening TCC checks:

July 24, 2023: Fixed in macOS Ventura 13.5.

- Apple Security Update: HT213820
- MITRE NVD: CVE-2023-32429

Conclusion

CVE-2023-32429 shows that even in secure systems like macOS, new threats can pop up. Luckily, Apple responded fast. Protect yourself by keeping your Mac updated and being cautious with app permissions. If you're interested in technical details, follow the references above for more.

Timeline

Published on: 07/27/2023 01:15:29 UTC
Last modified on: 08/01/2023 19:10:50 UTC