CVE-2022-42832 - How a Race Condition in Apple Devices (iOS, iPadOS, macOS) Opened the Door to Kernel Exploitation

In October 2022, Apple patched a serious vulnerability—CVE-2022-42832—which affected iPhones, iPads, and Macs running older systems. This security issue was a race condition: a tricky software problem where two parts of a program try to change something at the same time. These situations are a hacker’s playground because they can sometimes let someone break the usual rules of a system. Here’s an exclusive deep dive into what happened, why it mattered, and how it could have been abused.

Affected Devices: iPhones, iPads, and Macs with older OS versions

- Severity: Allows an app with root privileges to execute code as the kernel (the boss of your device)

Patched in:

- iOS 16.1 & iPadOS 16 (release notes)
- macOS Ventura 13 (release notes)
- Source: nvd.nist.gov/vuln/detail/CVE-2022-42832

Breaking Down the Race Condition

A race condition happens when software’s outcome depends on the unpredictable timing of events. Imagine two people trying to update a shared calendar at the same time—they may accidentally enter conflicting information.

In CVE-2022-42832, the problem was in a part of Apple’s kernel (the central part of the operating system responsible for managing security and resources). A special app—if it ran at root level (highest privileges)—could take advantage of a window of time when the kernel wasn’t locking things up correctly.

Think of it like this

// Pseudo-code showing the race condition
lock_resource();
// do something important, like granting access
unlock_resource();

If two threads (lines of code running at the same time) access a resource right AFTER it’s unlocked but BEFORE it’s properly closed, an attacker can sneak in and play tricks—changing behavior or redirecting execution.

Suppose your code to check if someone is allowed to do something looks like this

acquire_lock();
if (user_is_allowed) {
    do_sensitive_thing(); // like giving out kernel access
}
release_lock();

If someone manages to change user_is_allowed between the check and the action (maybe because the lock actually wasn't holding at the right time), they can trick your app into giving out privileges it never should have.

Exploitation: From Root to Kernel

Apple’s advisory notes this flaw could let a root app run arbitrary code as kernel. Normally, root is as powerful as an app can get—but the kernel is in charge of *everything*. Gaining kernel privileges lets you:

Imagine a malicious app with root

1. The app prepares two threads: one repeatedly requests access to a protected kernel resource, while the other tries to quickly release and reacquire that resource.
2. The attacker times these requests to hit during the tiny window where the resource isn’t properly locked.
3. The app slips in modified instructions or triggers unexpected kernel behavior, letting the attacker’s code run with kernel rights.

A simplified proof-of-concept might look like this (VERY simplified)

// Thread 1: repeatedly check & access resource
while(1) {
    if (try_access_resource()) {
        escalate_privileges();
    }
}

// Thread 2: manipulate or unlock resource timing
while(1) {
    force_unlock_resource();
}

*Note: Real-world exploits look much more complex and would require inside knowledge of Apple’s codebase!*

How Was It Fixed?

Apple’s engineers patched this bug in their “improved locking”. Basically, they closed the window—the resource is now properly locked so no one can sneak in at the wrong moment.

> Official wording:
> *A race condition was addressed with improved locking. This issue is fixed in iOS 16.1 & iPadOS 16, macOS Ventura 13.*

If you

- Keep your iOS/macOS devices updated—you’re safe.
- Run old devices that *can’t* get these updates—be careful what you install, since a root app could still exploit this (if someone wrote and deployed a working exploit).

Final Thoughts

CVE-2022-42832 could have let a dangerous app take total control of your Apple device—but thanks to timely patches, it was closed fast. Always update your devices, and remember: even the safest systems have cracks that clever (or patient) hackers might someday exploit.

Stay safe. Update often. And keep learning how these attacks work!

*This write-up is exclusive, plain-English, and for educational awareness only. If you enjoyed the deep dive, consider securing your own devices—and maybe even learning more about how operating systems handle privilege and security!*

Timeline

Published on: 11/01/2022 20:15:00 UTC
Last modified on: 11/04/2022 02:51:00 UTC