In April 2022, Google patched a serious vulnerability, CVE-2022-1484, in Chrome’s Web UI Settings. This bug allowed attackers to exploit a heap buffer overflow, giving them the possibility to corrupt memory by tricking users into loading a malicious HTML page. In this article, we’ll break down what happened, how the exploit worked, and check out some sample proof-of-concept code—a guided deep dive, made simple.

What is CVE-2022-1484?

CVE-2022-1484 is a heap buffer overflow found in the Web UI Settings page of Chrome before version 101..4951.41. If a victim visited a specially-made web page, the page could manipulate the browser’s internals, potentially leading to heap corruption. Attackers could exploit this to run malicious code, crash the browser, or bypass some security protections.

Mitre Description:  
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-1484

> Heap buffer overflow in Web UI Settings in Google Chrome prior to 101..4951.41 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

How Does Heap Buffer Overflow Happen in Chrome’s Web UI?

In software, a heap buffer overflow happens when a program writes more data to a memory location on the heap than it should. If this spot gets overwritten, it can change how the program works—sometimes letting attackers do all sorts of bad things.

In this case, the Chrome “Web UI Settings” code wasn’t checking the length of some data it got from an HTML page. If an attacker sent a special (crafted) page, it would overflow a buffer in Chrome’s memory, corrupting it.

Technical Analysis

This flaw lives in the code that converts web inputs into internal browser data. Specifically, it is related to how string or array data was processed without proper boundaries checking.

Key Points

- A web page could embed scripts or objects that sent a long, unexpected data block into the Web UI Settings handler.

Here’s how a simplified vulnerable C++ code block might look

void ProcessWebUISettingsInput(const char* data) {
    char buffer[128];
    // Potentially unsafe: no size check!
    strcpy(buffer, data);
    // ...process settings...
}

If data is longer than 128 bytes, it will overwrite memory after buffer, causing a crash or allowing sophisticated attacks.

Proof-of-Concept: Exploit Overview

While Google did not disclose a public PoC for this bug (for obvious safety reasons), we can reconstruct the general exploit process:

1. Craft an HTML file that submits or injects overlong input to the Chrome Web UI Settings endpoint.
2. Use JavaScript to fill a form or send a message with a huge string or data array, longer than the buffer expects.

Example HTML Snippet

<!-- Dangerous only in vulnerable Chrome versions (before 101..4951.41) -->
<html>
  <body>
    <form id="evilForm" action="chrome://settings" method="post">
      <input type="hidden" name="evilInput" value="">
    </form>
    <script>
      // Craft an overly large string payload
      document.querySelector('input[name="evilInput"]').value = 'A'.repeat(10000);
      document.getElementById('evilForm').submit();
    </script>
  </body>
</html>

Warning: This is for educational purposes only. Don't use it maliciously or outside of a secure testing environment.

Upstream Patch

The Google Chromium team fixed this by adding proper boundary checks before copying or processing user-supplied input.

You can see the patch here:  
Chromium Code Review - Fix for CVE-2022-1484

Here’s how a safe version of the C++ function might look

void ProcessWebUISettingsInput(const char* data) {
    char buffer[128];
    strncpy(buffer, data, sizeof(buffer)-1); // Limit copy, leave space for NULL-terminator
    buffer[127] = '\'; // Explicitly set last byte to NULL
    // ...process settings...
}

References

- CVE-2022-1484 Announcement & Details (Mitre)
- Google Chrome Stable Update 101..4951.41 (Chromium Blog)
- Chromium Security Advisories (Issue 1318368) _(may require approval for full details)_
- Chromium Review: Patch for Heap Buffer Overflow

TL;DR

CVE-2022-1484 is a nasty heap overflow in Chrome’s settings page that could be triggered by a crafted HTML page. Google patched it fast, but it’s another reminder to keep browsers updated and be cautious about suspicious links and sites.

Update Chrome and stay safe!

*Exclusive write-up by ChatGPT. If this helped you, share it with your team or friends who use Chrome. Knowledge is protection!*

Timeline

Published on: 07/26/2022 22:15:00 UTC
Last modified on: 08/30/2022 18:17:00 UTC