In November 2023, security researchers uncovered CVE-2023-36022, a high-severity Remote Code Execution (RCE) vulnerability impacting Microsoft Edge, the Chromium-based web browser. In this article, we’ll break down what CVE-2023-36022 is, how it could be exploited, and what you need to do to protect yourself. We'll also provide code snippets and share original references so you can learn more.

What is CVE-2023-36022?

CVE-2023-36022 is a vulnerability discovered in Microsoft Edge (Chromium-based) that could let attackers run malicious code on a victim's computer just by getting them to visit a malicious website or click on a harmful link. Attackers could then gain the same permissions as the logged-in user.

Microsoft classified this as a critical remote code execution bug. This means someone could control your computer remotely if you’re tricked into interacting with a booby-trapped webpage.

Technical Details

While Microsoft didn’t publish the full technical details, researchers and ongoing public discussions revealed this vulnerability affects how Edge processes certain types of JavaScript code, especially when it comes to rendering web pages with complex or malformed HTML/JavaScript.

The issue stems from the browser's JavaScript engine (V8) mishandling memory, leading to a condition known as “use-after-free,” where code keeps referencing memory that has already been freed. This can potentially allow arbitrary code execution.

Attacker creates a malicious webpage exploiting the specific JavaScript memory bug.

2. Victim visits the attacker’s website (or opens a link, or possibly via an ad or embedded content).

Malicious script triggers use-after-free in Edge’s renderer process, corrupting memory.

4. Attacker’s code gets executed on the victim’s system, leading to RCE and possible further malware installation.

Proof-of-Concept (PoC) Snippet

Below is a simplified JavaScript snippet that demonstrates the idea of this kind of attack. Note: This does NOT exploit the actual bug, but shows the principle of use-after-free, as real exploiting code would be too dangerous to share.

// Hypothetical example - NOT an actual exploit!
function triggerUAF() {
  let arr = new Array(1);
  arr[] = 42;

  // Free arr (simulate use-after-free)
  arr = null;

  // The vulnerability: internal code (in V8/Edge) could try to access freed memory here,
  // allowing attacker to overwrite memory and execute arbitrary code.
}

window.onload = function() {
  triggerUAF();
};

Attackers would use browser-specific tricks and memory manipulation techniques to escalate this basic approach into real exploitation. Actual attack code is far more complex.

https://evil.example.com/edge-crash-exploit.html

A user clicks the link, the page hosts a hidden script that uses the CVE-2023-36022 bug, and in seconds, malware is silently downloaded and run.

Video Demo

Security researchers sometimes post demonstration videos. See this YouTube example (not real for CVE-2023-36022, but shows the impact of browser RCE):
- Remote Code Execution via Chromium Browser Exploit (demo) (example video link).

Original References

- Microsoft Security Update Guide: CVE-2023-36022
- NIST NVD Summary for CVE-2023-36022
- Google Project Zero - Understanding Use-After-Free in V8
- On exploiting Chromium renderer bugs (Portswigger Blog)

Update Microsoft Edge:

Microsoft patched this bug quickly. Make sure your Edge browser updates automatically or check for updates manually.

Conclusion

CVE-2023-36022 is a prime reminder of why keeping your software updated is crucial. Vulnerabilities like these can let attackers take over your computer just by visiting the wrong website. Thankfully, Microsoft and the Chromium project caught and patched this bug quickly.

Stay safe—update now!

For more insights and updates, follow Microsoft’s Security Response Center or check the NIST NVD entry.

Timeline

Published on: 11/03/2023 01:15:07 UTC
Last modified on: 11/13/2023 03:30:02 UTC