CVE-2024-52318: Understanding the Incorrect Object Recycling and Reuse Vulnerability in Apache Tomcat and How to Keep Your System Secure

A new vulnerability, registered as CVE-2024-52318, has been discovered affecting a series of recent versions of the widely-used Apache Tomcat web server. In this article, we will provide an in-depth explanation of the vulnerability, why it is critical, and how to fix the issue to ensure your system's security. If your infrastructure relies on Apache Tomcat versions 11.., 10.1.31, or 9..96, it is essential to read on and take the necessary steps to protect your assets.

Background

Apache Tomcat is an open-source implementation of the Java Servlet, JavaServer Pages, Java Expression Language, and Java WebSocket technologies. It enables developers to create applications that are easily deployable and scalable on a web server. Tomcat is widely known for its flexibility, performance, and large community support.

The Vulnerability: CVE-2024-52318

CVE-2024-52318 refers to an incorrect object recycling and reuse vulnerability in Apache Tomcat 11.., 10.1.31, and 9..96. This security hole allows a malicious user to exploit the way Tomcat recycles and reuses certain objects, potentially leading to unauthorized access, data corruption, or denial-of-service attacks.

The vulnerability relates to the way Apache Tomcat handles its internal object pool. The pool is used for storing and reusing objects, such as sessions and connections while maintaining performance. The problem arises when an object, which should have been cleaned up before being returned to the pool, isn't cleaned up correctly.

The vulnerability can be demonstrated with the following hypothetical code snippet

// Some object pool implementation (flawed)
public class FlawedObjectPool {

    private ArrayList<Object> pool;

    public FlawedObjectPool() {
        pool = new ArrayList<>();
    }

    public Object getObject() {
        if (pool.isEmpty()) {
            return new Object();
        } else {
            Object obj = pool.remove();
            // Missing clean-up code!
            return obj;
        }
    }

    public void returnObject(Object obj) {
        pool.add(obj);
    }
}

In the getObject() method, objects removed from the pool should have been cleaned up before being returned for reuse. However, due to the missing clean-up code, the next user of these recycled objects may have access to the previous user's data or resources.

Exploit Details

An attacker aware of this vulnerability could craft a specific request, causing Tomcat to discard a vulnerable object without proper cleanup. Once the object returns to the pool and is later reused, the attacker gains unauthorized access and can use that to their advantage. For more details about this exploit, you can read this official advisory.

How to Fix the Issue

To safeguard your systems against this vulnerability, users are highly recommended to upgrade their Apache Tomcat installations to the following, corrected versions:

Apache Tomcat 9..97

These updated versions of Tomcat include critical patch updates addressing the incorrect object recycling and reuse issue. You can download the relevant files from the official Apache Tomcat downloads page.

In Conclusion

CVE-2024-52318 poses a severe risk to users running specific versions of Apache Tomcat. It is of paramount importance that you immediately upgrade to the corrected versions mentioned above. Always stay vigilant, keep your systems updated, and ensure the security of your infrastructure. By doing so, you'll protect your assets and ultimately contribute to a more secure web ecosystem.

Timeline

Published on: 11/18/2024 13:15:04 UTC
Last modified on: 11/18/2024 17:11:17 UTC