CVE-2024-21337 - Microsoft Edge (Chromium-based) Elevation of Privilege Vulnerability: Exploiting a Security Gap for Unintended Access

CVE-2024-21337 refers to an important security vulnerability that was recently discovered in the Chromium-based Microsoft Edge browser. The vulnerability is classified as an Elevation of Privilege (EoP) flaw, which, if exploited, could enable attackers to gain elevated permissions and execute malicious activities on the compromised system.

This blog post will dive deep into the CVE-2024-21337 vulnerability by examining its root cause, demonstrating a code snippet that reveals the issue, discussing potential exploit scenarios, and providing links to original references for further information.

Root Cause Analysis

The root cause behind the CVE-2024-21337 vulnerability lies in the improper handling of specific user input within Edge's Chromium engine. Due to the lack of proper input validation, attackers can inject malicious code that elevates their privileges on the system, leading to severe damage and unauthorized access to sensitive information.

The security loophole primarily affects the Windows operating system running the Microsoft Edge browser and is present in multiple versions of the Edge browser before the vulnerability was patched.

Code Snippet and Explanation

Here is a simplified code snippet that demonstrates the flawed input validation process within the Edge browser, allowing attackers to exploit the vulnerability:

// A hypothetical function responsible for granting user permissions
function grantPermissions(userInput) {
  // Lack of proper input validation allows an attacker to inject malicious code
  if (!validateUserInput(userInput)) {
    console.log("ERROR: Invalid user input");
    return;
  }

  // The vulnerable code segment
  var parsedInput = parseUserInput(userInput);
  executePermissions(parsedInput);
}

function validateUserInput(userInput) {
  // This method is either non-existent, incomplete, or improperly implemented
  return true; // As a result, attacker-manipulated input is passed to the next stage
}

function parseUserInput(userInput) {
  // Code that handles user input and passes it to the subsequent function
  return userInput;
}

function executePermissions(parsedInput) {
  // The injected malicious payload is executed here, allowing for EoP
  console.log("Permissions granted: " + parsedInput);
}

In the code snippet above, we see that the validateUserInput() function does not adequately validate the input from users, allowing malicious payloads to bypass security checks and proceed to the next stage. As a result, the injected code is executed in the executePermissions() function, causing the Elevation of Privilege.

Exploit Details and Scenarios

To exploit the CVE-2024-21337 vulnerability, an attacker would need to craft a malicious payload that can bypass the incomplete or improperly implemented input validation. This payload could be delivered via a phishing email, malicious website, or even hidden within seemingly innocuous ads.

Once the malicious payload is executed on the victim's system, the attacker gains elevated privileges, allowing them to perform such malicious activities as:

Original References

For more technical details on the CVE-2024-21337 vulnerability, as well as mitigation instructions, you can refer to these original references:

1. Microsoft Security Response Center - This official Microsoft page provides an in-depth breakdown of the vulnerability, including affected products, impact, and mitigation instructions.
2. CVE Details - A comprehensive summary of the CVE-2024-21337 vulnerability, its CVSS scores, and other relevant details.

Conclusion and Recommendations

The CVE-2024-21337 vulnerability highlights the potential risks in widely used software, such as Microsoft Edge. To protect your systems and data from this EoP vulnerability, we strongly recommend applying relevant security updates and patches provided by Microsoft to mitigate the risk.

Additionally, educating users about the dangers of phishing emails, navigating to suspicious websites, and avoiding clicking on malicious ads may help reduce the chances of falling victim to CVE-2024-21337 and similar vulnerabilities.

Timeline

Published on: 01/11/2024 22:15:46 UTC
Last modified on: 04/11/2024 20:15:19 UTC