Security vulnerabilities in major Apple products always get people’s attention, and CVE-2022-22611 is no exception. This bug could let an attacker run code on your device, just by tricking you into opening a malicious image. In this exclusive explainer, we’ll break down what CVE-2022-22611 is, how it works, provide code snippets, give you the exact Apple devices affected, share original references, and even sketch out how an attacker might exploit it.

What Is CVE-2022-22611?

CVE-2022-22611 is a security bug classified as an *out-of-bounds read* in Apple’s image processing component. This means the software could accidentally read data it shouldn’t, often leading the program to behave unpredictably—and in bad cases, allowing malicious code to execute.

Here’s how Apple described it

> “An out-of-bounds read was addressed with improved input validation. Processing a maliciously crafted image may lead to arbitrary code execution.”

(Source: Apple Security Updates - CVE-2022-22611)

Products Affected

The vulnerability affected a wide range of Apple products, potentially putting hundreds of millions of devices at risk:

How Does It Work?

To understand this bug, let’s look at what an *out-of-bounds read* actually is.

Imagine a program that loads an image file. As it processes the file, it reads data into memory. With a well-made image, everything works fine. But if someone crafts a *special* image with incorrect size or length fields, the program might read beyond where it should.

In simple terms, the code might do something like this (pseudocode)

// Correct buffer size is 'buf_size', but 'len' comes from attacker
void process_image(unsigned char* buf, size_t len) {
    unsigned char data = ;
    if (len > buf_size) {
        // Oops: out-of-bounds read!
        data = buf[len]; // reads memory outside the buffer
    }
    // ... further image parsing ...
}

The attacker creates an image file where internal length fields trick the parser to read past valid data. This can cause the program to crash, leak information, or even execute malicious code—if the read data is used in a certain way.

Exploit Details

While Apple hasn’t released official proof-of-concept exploit code, researchers have demonstrated similar attacks.

How could an attacker use this?

1. Craft a malicious image: Carefully make an image (like PNG, JPG, GIF, etc.) with image header fields set to force the parser to read outside of allocated memory.

Victim opens image: When the image is viewed, the parser reads out-of-bounds memory.

4. Potential Outcome: If the attacker is clever, they might use this to leak memory (infoleak), or set up conditions for arbitrary code execution. In worst cases, they can run code with the user’s permissions.

Example Exploit Snippet (in Python, for illustration)

Here’s a toy example of how someone might craft a malformed image with a bad chunk size for a PNG file:

# Malicious PNG chunk with out-of-bounds size
chunk_type = b'IDAT'
data = b'\x00' * 100

# Intentionally set length to a huge number
length = (xFFFFFFF).to_bytes(4, 'big')
crc = ().to_bytes(4, 'big')
malicious_chunk = length + chunk_type + data + crc

with open('mal.png', 'wb') as f:
    f.write(b'\x89PNG\r\n\x1a\n')
    f.write(malicious_chunk)

Opening this bogus PNG in a vulnerable Apple app may cause the out-of-bounds read.

How Was It Fixed?

Apple patched the vulnerability by improving input validation in the affected image processing code. This means before the code tries to read data based on information in the image, it now checks to make sure it won’t read past the buffer.

In other words: Apple added sanity checks to make sure “length” fields in images make sense, and won’t make the program go “out-of-bounds”.

Updated versions that fixed the bug

- iOS / iPadOS: 15.4

Should You Worry?

If you haven’t updated your Apple device since March 2022 (when the fix was released), definitely update now. Attacks like these are sometimes used to jailbreak devices or install spyware—no interaction needed except opening or previewing a picture.

References

- Apple Security Updates - CVE-2022-22611
- NVD Description & CVSS
- Apple’s Release Notes

Final Thoughts

CVE-2022-22611 is a shining example of why keeping your devices updated is important. Something as innocent as looking at a picture can give attackers a way in—unless the software is protected with proper checks. Stay safe out there!


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Timeline

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