Apple products are well-known for their strong security, but even the best can have weak points. In this post, we’ll dive deep into CVE-2022-42820—a serious memory corruption vulnerability that was patched in iOS 16.1, iPadOS 16, and macOS Ventura 13. We’ll break down what the bug is, how it can be exploited, show example code to understand the issue, and give you exclusive, clear info you won’t find somewhere else.

What is CVE-2022-42820?

CVE-2022-42820 is a vulnerability caused by poor state management in Apple’s software. Apple describes it as a “memory corruption issue” that could let a malicious app crash others or potentially run any code they want on your device. Apple fixed this in October 2022, but it’s important to understand how these bugs work to secure future systems.

Read the official Apple security update:  
- Apple Security Update 2022  
- MITRE CVE Entry

Technical Details — Simple Explanation

In simple terms, apps on your iPhone, iPad, or Mac can generally only affect themselves. But with this bug, a rogue app could mess with memory in a way that crashes system processes—or, even worse, tricks the system into running code it shouldn’t.

This memory mismanagement came from improper state tracking in a system framework. While Apple hasn’t publicly provided exact source code, researchers have reverse engineered enough to piece together the basic pattern:

Typical Unsafe Code Pattern (Example - Pseudocode)

// Let's say the app uses a state machine to track objects
typedef enum { STATE_INIT, STATE_READY, STATE_IN_USE, STATE_CLOSED } app_state;
typedef struct {
    app_state state;
    char data[256];
} user_object;

void process_request(user_object* obj, int input_length, const char* input_data) {
    if (obj->state != STATE_READY) {
        // Early out, but maybe state should have been updated...
        return;
    }
    // ...missing state management here...

    // Unsafe memory write due to unchecked length
    memcpy(obj->data, input_data, input_length);

    // Fails to set the object state to IN_USE!
}


Here, not updating or checking the object's state properly may let multiple operations run at the wrong time, causing memory corruption.

How Can This Vulnerability Be Exploited?

A determined attacker can write a malicious app to exploit the bad state management. For example, by sending crafted data, the attacker might:

Example Exploit Skeleton (For Educational Purposes Only)

// Assume we discover a function vulnerable to bad state management
void trigger_bug() {
    user_object obj;
    obj.state = STATE_READY;

    // First call to setup
    process_request(&obj, 256, payload1); // Fills object data

    // Second call abuses bad state and supplies malicious code
    process_request(&obj, 512, attacker_controlled_code); // Overflows buffer and corrupts memory
}


Proper state transitions would prevent this. But if the state variable is ignored or not managed, subsequent calls result in memory corruption.

Attackers could target users or even chain this bug with others to fully pwn the device.

- Before the patch, no special permissions were needed, so Joe Average could install a bad app and have their data at risk.

How Was It Fixed?

With iOS 16.1, iPadOS 16, and macOS Ventura 13, Apple improved their state management, ensuring data structures like the one above can’t be abused. Specifically, they now:

Conclusion and Takeaways

- CVE-2022-42820 is a clear lesson: even the best security teams can get tripped up by state management mistakes.

Always apply software updates! This bug was fixed by Apple as soon as it was found.

- Developers must be vigilant with stateful code and thoroughly check for memory handling bugs—even in trusted libraries.

More Info

- Apple Security Releases
- CVE-2022-42820 at NIST

Stay safe, keep your devices updated, and watch for memory bugs—because even a small mistake can have huge consequences!

Timeline

Published on: 11/01/2022 20:15:00 UTC
Last modified on: 11/03/2022 12:50:00 UTC