Apple devices are generally seen as secure, but occasionally, a critical bug slips through. One such bug, CVE-2022-32922, caught the attention of security researchers and hackers alike. This post breaks down how this use-after-free vulnerability in WebKit could have allowed attackers to run arbitrary code on your device—and how Apple fixed it.

1. What is CVE-2022-32922?

CVE-2022-32922 is a “use-after-free” memory issue found in WebKit, the engine behind Safari and most web content on Apple devices.

Put simply:  
When you visit a malicious website, that site could trick Safari (or any app using WebKit) into using a chunk of memory after it's been freed—resulting in unpredictable behavior or even letting the attacker take control of your device.

Safari before v16.1

- iOS/iPadOS before 16.1

macOS Ventura before 13

Apple fixed this bug by improving memory management, making this attack much harder or impossible.

Official References

- Apple Security Updates
- NVD Entry for CVE-2022-32922

2. What is a “Use-After-Free” Bug?

A use-after-free (UAF) happens when a program keeps using memory after it told the operating system it was done with it. Exploiting a UAF can let a hacker insert their own malicious code and trick the program into running it.

Illustration

// Incorrect memory management (vulnerable pattern)
char *buf = malloc(100);
free(buf);           // Memory is freed
strcpy(buf, "boom"); // buf shouldn't be used here!


In WebKit, these bugs can occur in highly complex parts of code, triggered by crafted JavaScript running in the browser.

3. Diving Into The WebKit Bug

The details of this specific bug are not fully public, but based on Apple’s own patch notes, the vulnerability lies in how WebKit processes certain objects in memory (probably DOM objects or similar).

Hypothetical Vulnerable Code Pattern

void processObject(MyObject *obj) {
    // Some action that may free memory
    if (obj->shouldRelease) {
        free(obj);
    }
    // Later, code tries to use obj again
    if (obj->needsProcessing) {
        obj->doSomething();
    }
}

An attacker could control the data in obj, making sure it gets used after being freed. If they can fill the freed memory slot with their own data, they can hijack the program’s behavior.

4. Exploiting the Bug: Proof-of-Concept (POC)

While the exact exploit for CVE-2022-32922 is undisclosed for responsible reasons, there are public examples of similar WebKit UAF attacks.

Example JavaScript exploit strategy

// Allocate many objects
let arr = [];
for (let i = ; i < 10000; i++) {
    arr.push(document.createElement('div'));
}

// Trigger garbage collection (simulated)
for (let i = ; i < 10000; i++) {
    arr[i] = null;
}

// Manipulate memory heuristically to reoccupy freed slots
let evilArray = [];
for (let i = ; i < 10000; i++) {
    evilArray.push({exploit: "data"});
}

// Hope that the next access hits our crafted object
// (in real attack, this would trigger code execution)

This is, of course, a simplified illustration. Real exploits are much more complex and require deep understanding of memory layout, object lifecycles, and sometimes brute-force spraying of memory.

More Reading

- WebKit Use-After-Free: Modern JavaScript Exploitation
- Phrack - Modern macOS Exploitation

Safari 16.1+

- iOS/iPadOS 16.1+

Always update your devices. Most hacks work only on old versions.

- If you’re curious, follow WebKit security advisories—Safari is a real-world favorite for advanced attackers.

8. Resources

- Apple’s Security Update List
- WebKit Security Announcements
- Common Vulnerabilities and Exposures
- Google Project Zero WebKit Exploit Writeups

*This post aims to simply explain a serious browser bug fixed by Apple in late 2022, with examples, links, and general advice on web security.*

Timeline

Published on: 11/01/2022 20:15:00 UTC
Last modified on: 11/02/2022 17:52:00 UTC