CVE-2023-36559: Understanding the Microsoft Edge (Chromium-based) Spoofing Vulnerability

The CVE-2023-36559 vulnerability, recently discovered and reported in the Chromium-based, Microsoft Edge browser, underscores the fact that phishing attacks still pose an ongoing threat to internet users. The vulnerability allows attackers to exploit the Edge browser to mislead users by displaying a fake website address in the URL bar, causing them to believe they are accessing a legitimate website. In this post, we will take a deep dive into this exploit, scrutinize the code snippets and identify ways to mitigate the impact.

How the Vulnerability Works

By exploiting the CVE-2023-36559 vulnerability, attackers create a spoofed URL that is visually identical to the legitimate URL of a well-established website. This could be a popular login page for a reputable organization, a social media platform, or a shopping website. Once a user clicks on this link, they are unknowingly redirected to a fraudulent site, where the attacker is then able to harvest sensitive data, such as passwords and credit card numbers.

Code Snippet

The core spoofing technique used in the exploit falls under a technique referred to as "URL Encoding". It involves mixing encoded characters with legitimate ones in order to create a misleading display. Here's a simple example:

const spoofedURL = "https://www.example.com%2F%20%2E%2E%2Flogin/";;

function manipulateAddressBar() {
    window.history.pushState({"pageTitle": "Spoofed Login Page"}, "", spoofedURL);
}

In this example, %2F represents /, %20 signifies a space character, and %2E%2E simulates ..(double dots). These encodings were manipulated to create a deceptive URL that mimics a legitimate website address.

Original References

1. Chromium Project's Bug Tracker: This vulnerability was initially reported in the Chromium project's bug tracker on link. The official issue report contains all the details, discussions, and updates.

2. CVE-2023-36559: The official MITRE CVE listing for this vulnerability can be found at link. This page provides a high-level overview, including a description, impact metrics, and affected software.

3. Microsoft Security Advisory: Microsoft has released a security advisory on the vulnerability here. The advisory details the affected versions of Edge and outlines the steps users should follow to protect themselves from this exploit.

Possible Mitigation

Given the nature of this vulnerability, it's essential to always browse the internet with caution, verify website certificates (HTTPS), and check the legitimacy of URLs before entering sensitive information on any website. Additionally, keeping the browser updated with the latest patches can minimize the risk of such exploitation.

Microsoft has released an update addressing this vulnerability; users should apply the security update as soon as possible. The recommended steps to update Microsoft Edge can be found at this link.

To mitigate this issue on the developers' side, website owners can implement strict Content Security Policies (CSPs) to prevent code injection and enforce secure connections by enabling the Strict-Transport-Security header. Examples are provided in the links below:

1. Content Security Policy: link

2. HTTP Strict Transport Security: link

Conclusion

The CVE-2023-36559 vulnerability showcases how even the most sophisticated browsers can be vulnerable to a well-crafted attack. It's essential for developers to continuously monitor security threats, regularly patch software, and implement secure practices. For end-users, online vigilance and prompt updates are crucial to keeping our personal information safe in this connected world.

Timeline

Published on: 10/13/2023 21:15:51 UTC
Last modified on: 10/18/2023 20:01:09 UTC