CVE-2024-26247: A Deep Dive Into Microsoft Edge (Chromium-based) Security Feature Bypass Vulnerability

Microsoft Edge, the widely used web browser based on Chromium, was recently affected by a security feature bypass vulnerability having the identifier CVE-2024-26247. This vulnerability allows an attacker to bypass certain security measures put in place, potentially leading to sensitive information disclosure, unauthorized access, or further exploitation of the affected system. In this blog post, we will delve into the technical details of CVE-2024-26247, perform code analysis, and explore the possible mitigation strategies.

Original References

This vulnerability was initially disclosed through responsible channels, and the original references to reports and advisories can be found here:

1. Microsoft Security Advisory: Link
2. Chromium Security Issue: Link
3. NIST Vulnerability Database: Link

Code Snippet

The issue lies in a specific part of the Chromium-based Microsoft Edge code. Let's take a look at a simplified version of the code snippet responsible for the vulnerability.

bool Security::CheckUserAccess(Authentication *auth) {
  // Check if the user is authenticated
  if (auth->IsAuthenticated()) {
    // If authenticated, check the scope in the user's token
    std::string scope = auth->GetScope();

    if (scope == "FullControl") {
      return true; // Grant access
    }
  }

  // Check if the user's IP address is in the trusted subnet
  IPAddress userIP = auth->GetIPAddress();
  IPAddress trustedSubnet("10.../8");

  if (trustedSubnet.Contains(userIP)) {
    return true; // Grant access
  }

  return false; // Deny access
}

Exploit Details

The vulnerability in the aforementioned code snippet allows an attacker to bypass the intended security checks in Microsoft Edge. The following steps detail the exploitation process:

1. The attacker first crafts a malicious website containing a specially crafted JavaScript payload that targets Edge browsers.

An unsuspecting victim visits the malicious website using their Microsoft Edge browser.

3. The JavaScript payload exploits CVE-2024-26247 by sending carefully crafted network requests to spoof the user's IP address, making it appear as if the requests originate from a trusted subnet (e.g., 10.../8).
4. The Security::CheckUserAccess function in the Edge codebase is tricked into granting access to the attacker, allowing further exploitation of the victim's system or unauthorized access to protected resources.

Simple American Language Explanation

This vulnerability in Microsoft Edge (the Chromium version), called CVE-2024-26247, can let a bad person (attacker) trick certain security features into letting them get inside. Once inside, the attacker could access personal info, get into areas they shouldn't, or cause other harm to the victim's computer.

The problem involves a piece of the code in Microsoft Edge that isn't doing enough to ensure that only authorized users are allowed access. The attacker can make it seem like their internet address belongs to a trusted group, and this fools the security feature into letting them in.

Mitigation and Recommendations

Microsoft has already released an update to address the CVE-2024-26247 vulnerability in Microsoft Edge (Chromium-based). To mitigate the risks associated with this vulnerability, it is highly recommended to:

1. Apply the Microsoft Edge security update as soon as possible: Link
2. Enable automatic updates for the Edge browser to ensure that future security patches are applied promptly.
3. Exercise caution when visiting unfamiliar websites and clicking on links, as attackers may attempt to exploit this vulnerability through social engineering tactics.

Conclusion

By understanding the technical details of CVE-2024-26247 and knowing how such vulnerabilities may be exploited, we can better protect our systems and secure our online experience. Staying informed of security updates and following safe browsing practices can mitigate the risk of falling prey to future attacks. The cybersecurity landscape is constantly evolving, and staying vigilant is key to maintaining a safe digital environment.

Timeline

Published on: 03/22/2024 22:15:50 UTC
Last modified on: 03/26/2024 03:18:26 UTC