Google Chrome is one of the most widely used web browsers today. One of the things that keeps it secure is its regular updates patching newly found vulnerabilities. In August 2023, a critical issue was addressed: CVE-2023-4349—a dangerous vulnerability in Device Trust Connectors. This post explains what happened, how it works, and how attackers could have exploited it.
What is CVE-2023-4349?
CVE-2023-4349 describes a use-after-free bug found in the Device Trust Connectors of Google Chrome, affecting versions before 116..5845.96. With this bug, a specially crafted HTML page could cause memory corruption (specifically, heap corruption), opening the door for remote attackers to run their own code on the victim’s computer.
Severity: High
Chromium Issue: Chromium Issue 1461685
Fixed in: Chrome 116..5845.96 (August 2023)
What’s a Use-After-Free Bug?
A use-after-free bug happens when a program keeps using a chunk of memory even after it’s been freed (released back to the system). If a crafty attacker can fill this “freed” memory with something else before it gets used, they might control how the program works, hijack it, or make it crash.
It’s kind of like tearing up a note but continuing to read it as if nothing's changed—a sneaky attacker could rewrite the note before you read it again.
The Vulnerable Component: Device Trust Connectors
Device Trust Connectors are used in Chrome to help organizations check that devices meet certain trust requirements before they access protected content. The vulnerability was rooted in how Chrome managed the memory for these connectors.
Exploit Overview
A remote attacker could trick a user into visiting a crafted HTML page. This page could trigger the use-after-free scenario by manipulating the way Chrome handles Device Trust Connectors, ultimately leading to:
Arbitrary code execution—letting the attacker run their code on the user’s machine.
No user interaction beyond just loading the web page was required for this to happen.
Sample Exploit Flow (Simplified Pseudocode)
While the real exploit would depend on the attacker’s deeper understanding of Chromium's internals, here’s a simplified demonstration showing how use-after-free bugs can be exploited in browsers:
// Example logic for a use-after-free style attack in HTML/JavaScript
let obj;
// Step 1: Create an object tied to Device Trust Connectors
obj = createDeviceTrustObject();
// Step 2: Remove references, causing the browser to free the object
releaseDeviceTrust(obj);
// Step 3: Force browser to reuse the freed memory for a different purpose
for (let i = ; i < 10000; i++) {
allocateFakeObject(i); // Fills the freed memory with controlled data
}
// Step 4: Trigger the use of the old, now-freed object
obj.triggerAction(); // If successful, this operates on attacker data!
This is a very high-level hypothetical scenario. Actual exploits may use sequences of DOM manipulation, event handling, and abuse browser-specific features.
Chromium Security Bug Tracker:
Issue 1461685: Use after free in Device Trust Connectors
Chrome Release Notes:
CVE details:
How Was It Fixed?
The Chrome security team updated the browser to make sure the Device Trust Connector object can’t be used after it's freed. This involved better memory management and stricter lifecycle controls.
*If you're running an older version of Chrome (before 116..5845.96), make sure to update it promptly!*
Why Does This Matter?
Memory corruption bugs like use-after-free are a favorite tool of attackers. They are hard to detect and can lead to:
Taking over computers
Because Chrome is used everywhere, even a single vulnerability can put millions at risk. Quick patches and updates are crucial for safety.
Summary
CVE-2023-4349 was a high-severity use-after-free vulnerability in Google Chrome’s Device Trust Connectors. Attackers could exploit this with a crafted HTML page to potentially execute arbitrary code. The bug was patched in version 116..5845.96. Always update your browser to stay ahead of such risks.
Timeline
Published on: 08/15/2023 18:15:00 UTC
Last modified on: 08/27/2023 03:15:00 UTC