CVE-2024-6162: Undertow High Severity Vulnerability Guide

by Viktoria Ivanova 58 views

Hey guys! Let's dive into a high-severity vulnerability, CVE-2024-6162, recently discovered in Undertow. This is something you definitely want to be aware of, especially if you're using Undertow in your projects. We'll break down what the vulnerability is, why it's a big deal, and how you can fix it. So, buckle up and let's get started!

Understanding CVE-2024-6162

At the heart of this issue is a mishandling of URL-encoded request paths within Undertow's AJP listener. The core problem arises when concurrent requests are processed. Imagine a busy server handling multiple requests simultaneously; this is where things get tricky. The same buffer is used to decode the paths for these multiple requests, which can lead to a jumbled mess of path information.

Why is this happening? Think of it like a whiteboard where multiple people are trying to write at the same time. The result is often a confusing overlap of information. In this case, the overlapping information can cause the server to access the wrong path. The consequences? You might see frustrating “404 Not Found” errors or other application hiccups. More critically, this can lead to a denial of service (DoS), where legitimate resources become inaccessible because of the path confusion. Nobody wants their site or application going down, right?

In simpler terms, this vulnerability means that under heavy load, your server might get confused about which page or resource a user is requesting. This confusion can lead to errors and even crash parts of your application. It’s like trying to find a specific book in a library where the shelves are constantly being rearranged by other people – super frustrating and inefficient.

Specifically, the vulnerability lies in the undertow-core-2.0.28.Final.jar library. If you're using this version (or possibly earlier vulnerable versions), you're at risk. To give you an idea of the scope, this library is often pulled in as a dependency of spring-boot-starter-undertow, which is a common component in Spring Boot applications. So, if you're in the Spring Boot world, this is definitely something to pay attention to.

Technical Details: Diving Deeper

For those who love the technical nitty-gritty, let's dig into the details. The vulnerability stems from how Undertow handles the decoding of URL-encoded paths when using the AJP (Apache JServ Protocol) listener. The AJP listener is commonly used in setups where Undertow is behind a web server like Apache HTTP Server.

When multiple requests come in concurrently, Undertow uses a shared buffer to decode the URL paths. Because these requests are processed simultaneously, the buffer can get overwritten with path information from different requests. This interleaving of data leads to the server misinterpreting the requested path.

The impact is significant because a successful exploitation of this vulnerability can lead to more than just occasional errors. It can create a state where your application becomes unreliable, serving incorrect content or failing to serve content altogether. In a high-traffic scenario, this can quickly snowball into a major outage.

From a CVSS (Common Vulnerability Scoring System) perspective, this vulnerability scores a concerning 8.7. This high score is due to its network-based attack vector, low attack complexity, no required privileges or user interaction, and its potential impact on availability. This score underscores the seriousness of the vulnerability and the need for timely remediation.

Identifying Vulnerable Systems

So, how do you know if you're affected? The key is to check if you're using the vulnerable library, undertow-core-2.0.28.Final.jar, or a prior version that is also affected. You'll need to examine your project's dependencies. If you're using Maven, you can check your pom.xml file or run the mvn dependency:tree command to see the dependency hierarchy.

Look for the undertow-core dependency. If you see 2.0.28.Final listed, you're vulnerable. Also, remember that undertow-core is often pulled in transitively through spring-boot-starter-undertow. So, even if you don't directly depend on undertow-core, you might still be affected if you're using a vulnerable version of spring-boot-starter-undertow.

If you're using other build tools like Gradle, you'll need to use the equivalent commands to inspect your project's dependencies. The goal is to identify whether undertow-core-2.0.28.Final is present in your dependency tree. Don’t skip this step! Knowing your exposure is the first step toward fixing the issue.

WebGoat8 and the Vulnerability

Interestingly, this vulnerability was found in the WebGoat8 project, specifically in the commit 7eeb88fd39d36dd93918e5286e18c3b3a6834a91. WebGoat is a deliberately insecure web application, often used for security training and testing. The fact that this vulnerability exists within WebGoat highlights the importance of regular security audits and keeping dependencies up to date, even in non-production environments.

The vulnerability's presence in WebGoat provides a valuable opportunity for security professionals and developers to understand the mechanics of the issue and practice exploit mitigation. If you're involved in web application security, exploring this vulnerability within WebGoat can be a fantastic learning experience.

Remediation: How to Fix It

Now for the good news: there's a fix! The recommended solution is to upgrade your Undertow version. The fix resolution for io.undertow:undertow-core is version 2.2.33.Final. If you're using Spring Boot, the direct dependency fix resolution for org.springframework.boot:spring-boot-starter-undertow is version 3.0.0 or later.

Upgrading is crucial. In Maven, you'd update the version number in your pom.xml file. For example, if you're using Spring Boot, you might need to upgrade your Spring Boot version to one that uses the fixed Undertow version. Spring Boot makes it relatively easy to manage dependencies, so this should be a straightforward process.

If you can't upgrade immediately, you should explore temporary mitigation strategies. However, these are generally less desirable than a full upgrade because they might introduce other complexities or limitations. It's always best to apply the official fix as soon as possible.

Step-by-Step Upgrade Guide

To make the upgrade process crystal clear, here's a step-by-step guide:

  1. Identify your current Undertow version: As we discussed earlier, use your build tool's dependency analysis features to find the undertow-core version.
  2. Check Spring Boot version (if applicable): If you're using Spring Boot, find out which version you're on. Spring Boot manages Undertow, so upgrading Spring Boot might be the easiest path.
  3. Review Spring Boot release notes: If upgrading Spring Boot, check the release notes for the target version to see which Undertow version it includes.
  4. Update dependencies: Modify your pom.xml (Maven) or build.gradle (Gradle) file to use the fixed versions.
  5. Test thoroughly: After the upgrade, thoroughly test your application. Pay special attention to areas that handle a lot of concurrent requests or URL manipulation.

Remember, testing is key! You want to ensure the upgrade hasn't introduced any regressions or unexpected behavior.

CVSS 4 Score Breakdown

Let's break down that CVSS 4 score of 8.7 to understand the vulnerability's severity. CVSS, or Common Vulnerability Scoring System, provides a standardized way to assess the severity of security vulnerabilities. A score of 8.7 is definitely in the "high severity" range, indicating a serious issue.

The score is derived from various metrics, including:

  • Attack Vector (Network): This means the vulnerability can be exploited over the network, making it remotely exploitable.
  • Attack Complexity (Low): The complexity of exploiting this vulnerability is low, meaning it's relatively easy for an attacker to take advantage of it.
  • Privileges Required (None): No special privileges are needed to exploit this vulnerability.
  • User Interaction (None): No user interaction is required to trigger the vulnerability. An attacker can exploit it without any action from the victim.
  • Impact (Availability): The primary impact of this vulnerability is on availability. An attacker can cause a denial of service by exploiting the path mishandling.

These metrics combine to paint a picture of a vulnerability that's relatively easy to exploit and can have a significant impact on your application's availability. This is why it's critical to address it promptly.

Final Thoughts

The CVE-2024-6162 vulnerability in Undertow is a serious issue that you should address if you're using a vulnerable version. The potential for denial of service makes this a high-priority fix. By understanding the vulnerability, identifying affected systems, and upgrading to the fixed version, you can protect your applications and keep them running smoothly.

Remember, staying on top of security vulnerabilities is an ongoing process. Regularly reviewing your dependencies and applying security patches are crucial steps in maintaining a secure application environment. Keep your systems updated, guys, and stay safe out there!

Summary of Key Takeaways

  • Vulnerability: CVE-2024-6162 in Undertow
  • Affected Library: undertow-core-2.0.28.Final.jar
  • Impact: Denial of Service (DoS)
  • Fix: Upgrade to undertow-core-2.2.33.Final or Spring Boot 3.0.0 or later
  • CVSS Score: 8.7 (High Severity)
  • Remediation: Upgrade your Undertow version

Stay vigilant and keep your applications secure!