Google Chrome, the world’s most popular web browser, prides itself on security. But even the best can slip up. In late 2023, security researchers and Google themselves disclosed CVE-2023-5482: a high-severity vulnerability in Chrome’s handling of USB data that could let remote attackers execute out-of-bounds memory access. The root cause? Insufficient data validation in the USB API, with dangerous consequences.

In this exclusive deep-dive, we break down what CVE-2023-5482 is, how it works, and show a simplified version of how an attack could look in practice.

What Is CVE-2023-5482?

CVE-2023-5482 affects Google Chrome before version 119..6045.105. The bug lives in how Chrome interacts with USB devices through web APIs. A skilled attacker could craft an HTML page that, when opened, could trigger Chrome to perform “out of bounds” memory access—reading or writing memory it shouldn’t touch.

*Severity:* High
*Affected versions:* Chrome prior to 119..6045.105
*Attack vector:* Remote, via an HTML page
*Component:* USB (WebUSB API)

Understanding the Problem

Modern browsers let web pages communicate with hardware like USB devices using the WebUSB API. Chrome’s implementation did not sufficiently validate incoming data from USB devices. If a page supplied unexpected, oversized, or specially crafted data, Chrome could misinterpret it, allowing the attacker to poke at memory they shouldn’t have access to.

Stealing Sensitive Data: Out-of-bounds reads could leak information from memory.

- Browser Crash / Denial of Service: Memory corruption could crash Chrome.
- Potential Code Execution: In some scenarios, control over memory can lead to running attacker code.

Timeline

- Reported: October 2023 (Chromium issue 149493)
- Patched: Chrome 119..6045.105 (Release Notes)

Exploit Example

Let’s break down a stylized example. (This is a safe, educational snippet and will NOT exploit Chrome.)

// Hypothetical attack using the WebUSB API
async function triggerUSBBug() {
  // Request connection to any USB device
  let device = await navigator.usb.requestDevice({ filters: [{}] });

  // Open the device
  await device.open();

  // Craft a maliciously large data buffer
  let payload = new Uint8Array(1024 * 1024); // overly large, unexpected size

  // Try to send the crafted buffer to the device
  await device.transferOut(1, payload);

  // If Chrome doesn't validate 'payload' length,
  // it might perform out-of-bounds write/read
}

window.onload = () => {
  triggerUSBBug().catch(err => console.log(err));
};

In this hypothetical scenario, the attacker tricks a user into connecting a USB device, then sends a huge, carefully crafted payload. The buggy Chrome version wouldn’t properly check if this data fits, leading to corruption.

> Note: The actual Chrome bug had more constraints and was more subtle. The above is only a teaching illustration.

How Was It Fixed?

Google’s engineers quickly patched Chrome, adding more robust validation before reading or writing USB data buffers. Now, no matter what a page or USB device throws at Chrome, it checks that the amount and format of data is safe before proceeding.

Relevant patch:
You can see details of the fix in the Chromium Gerrit review.

Update Chrome: If you’re not at version 119..6045.105 or later, update immediately.

- Be wary of suspicious USB devices: Especially if you’re prompted to allow access from unknown sites.

Further Reading

- Official Chrome Release Notes
- MDN WebUSB API Documentation
- Project Zero: How memory corruption bugs are exploited

Conclusion

CVE-2023-5482 is a classic lesson: even advanced browsers like Chrome can trip up on hardware interfaces. Strict data validation is not an option—it’s a necessity. While Google quickly closed the gap, it’s a reminder for developers (and users!) to treat hardware and APIs with care.

Timeline

Published on: 11/01/2023 18:15:09 UTC
Last modified on: 11/14/2023 03:15:11 UTC