In early 2022, Apple released security updates patching a critical vulnerability known as CVE-2022-22613. This bug was an out-of-bounds write in Apple's operating systems that could let malicious apps execute code with kernel privileges—effectively letting attackers take over devices completely.

In this post, I’ll break down what CVE-2022-22613 means in plain language, walk you through the impact, look at simplified code illustrating the bug, give links for further reading, and summarize how the exploit works.

What actually is CVE-2022-22613?

Apple's technical note is understated:  
> "An out-of-bounds write issue was addressed with improved bounds checking."  
> (source)

What that means: there was a bug in the code where Apple’s kernel (the operating system's core) failed to check that it was writing inside the correct memory range. A special request to the system, crafted in a certain way, could cause it to write outside the boundaries of a memory region—possibly overwriting sensitive data. A clever attacker could use this out-of-bounds write to seize control of the device’s most trusted code.

watchOS 8.4.x and earlier (fixed in 8.5)

Nearly all recent Apple devices were at risk before these updates.

Understanding Out-of-Bounds Write

"Out-of-bounds write" means a program writes data past the end (or before the start) of where it’s supposed to. Imagine you had a box with five slots, but you stored something in slot 6—there is no slot 6, so you could overwrite something important!

Kernel memory is highly privileged. A mistake there is way more dangerous than in a normal app. With kernel-level access, attackers can bypass all security checks on your device.

Simplified Code Example

_This is a made-up, simplified example to illustrate the issue. It's not Apple’s real code, but it shows how such a bug can happen._

// Assume arr is an array of 8 elements
int arr[8];

void kernel_handler(int index, int value) {
    arr[index] = value; // No bounds checking!
}

If a user asks the kernel to write to, say, index = 12, the code will happily overwrite memory that doesn't belong to arr, possibly something critically important.

A secure implementation would check the bounds

void kernel_handler(int index, int value) {
    if (index >=  && index < 8) {
        arr[index] = value;
    } else {
        // Handle error
    }
}

Apple patched CVE-2022-22613 reportedly by adding such checks.

How Could Attackers Exploit This?

By abusing this out-of-bounds write, a malicious application could overwrite function pointers, structures, or other kernel data. That could let it get the kernel to execute the attacker's own code, essentially breaking out of Apple's secure "sandbox." A successful attack would give:

Potential for jailbreaking or persistent rootkits

Attackers would need a crafted app (possibly delivered through a malicious website, side-loaded software, or other vector). Fortunately, there’s no evidence that this flaw was widely exploited “in the wild” before Apple issued the fix.

Exploit Details

While Apple does not publish full exploit code, security researchers often reverse-engineer patches to find the vulnerable functions. In most kernel out-of-bounds issues, exploit steps might include:

Use that code execution to disable security, elevate privileges, or install persistent malware.

*Note*: Due to the danger and ethics, real world "weaponized" exploit code is not shared here.

tvOS 15.4

- Especially if you use an older device that might not get more updates, consider the risk of unpatched vulnerabilities.

References

- Apple Security Update: CVE-2022-22613  
- NIST CVE Database: CVE-2022-22613
- Apple iOS and iPadOS 15.4 Release Notes
- Project Zero: Out-of-Bounds Write Issues Explained

In Short

CVE-2022-22613 was a critical vulnerability affecting almost all modern Apple devices due to missing bounds checks in the kernel. The flaw could have let a rogue app take complete control of your iPhone, Mac, or Apple Watch, but Apple patched it in March 2022. Staying up to date with software fixes is the best way to protect your devices.

If you want to learn more about memory corruption and kernel exploits, check out the references above. And always keep your devices patched!

Timeline

Published on: 03/18/2022 18:15:00 UTC
Last modified on: 03/24/2022 16:40:00 UTC