CVE-2023-21830: Critical Vulnerability in Oracle Java SE And Oracle GraalVM Enterprise Edition Serialization Component

A newly discovered vulnerability known as CVE-2023-21830 has been found in the Oracle Java SE and Oracle GraalVM Enterprise Edition products. Specifically, the vulnerability lies in the Serialization component of these products. The affected versions are Oracle Java SE: 8u351, 8u351-perf; Oracle GraalVM Enterprise Edition: 20.3.8, and 21.3.4. This vulnerability can be easily exploited by an unauthenticated attacker with network access via multiple protocols, and a successful attack could result in unauthorized update, insert, or delete access to some of the data accessible by Oracle Java SE, Oracle GraalVM Enterprise Edition.

It is important to note that this vulnerability primarily affects Java deployments that are running sandboxed Java Web Start applications or sandboxed Java applets, and that load and run untrusted code from the internet. This vulnerability is not applicable to Java deployments in servers that load and run only trusted code, which is typically installed by an administrator.

The Common Vulnerability Scoring System (CVSS) 3.1 Base Score for this vulnerability is 5.3 (Integrity impacts). The CVSS Vector is: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).

Code Snippet

While the exact code exploit for this vulnerability is not publicly disclosed for security reasons, below is a simple example of Java code dealing with serialization and deserialization, where the vulnerability could possibly exist:

import java.io.*;

public class SerializationExample {
    public static void main(String[] args) {
        try {
            MyClass obj = new MyClass("Sample Text", 1234);

            FileOutputStream fos = new FileOutputStream("serializedFile.ser");
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            oos.writeObject(obj);
            oos.close();
            fos.close();

            FileInputStream fis = new FileInputStream("serializedFile.ser");
            ObjectInputStream ois = new ObjectInputStream(fis);
            MyClass newObj = (MyClass) ois.readObject();
            ois.close();
            fis.close();

            System.out.println("Object deserialized successfully");
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

class MyClass implements Serializable {
    private static final long serialVersionUID = 1L;
    private String text;
    private int number;

    public MyClass(String text, int number) {
        this.text = text;
        this.number = number;
    }
}

Original References

For more information on the vulnerability, you can refer to the following resources provided by Oracle:

1. Oracle Critical Patch Update Advisory - April 2023: This advisory contains all the details related to the vulnerability, including the CVE number, description, and affected products and versions.
2. Oracle Java SE Risk Matrix: This document provides a comprehensive list of all known security vulnerabilities in Oracle Java SE and their corresponding CVSS scores.

Exploit Details

As mentioned earlier, this vulnerability can be exploited by an unauthenticated attacker with network access via multiple protocols to compromise Oracle Java SE, Oracle GraalVM Enterprise Edition products. Since the vulnerability lies in the Serialization component of the affected products, it is possible that the attacker can exploit it by crafting malicious serialized objects and sending them across the network to the target system.

Organizations should ensure that their systems are patched promptly and that they follow best practices to mitigate the risk of exploitation. This includes:

1. Keeping software up-to-date: Always ensure the latest patches and updates are installed on all systems and applications.
2. Implementing strong network security: Protect your network from unauthorized access by implementing strong firewalls, intrusion detection, and prevention systems.
3. Securing Java Web Start applications and Java applets: Restrict access to only trusted sources and avoid running untrusted code from the internet.
4. Monitoring and logging: Implement monitoring and logging solutions to detect and respond to early signs of a security breach or unauthorized access.

Adopting these best practices will help minimize the risk of exploitation and ensure the security of your organization's systems and data.

Timeline

Published on: 01/18/2023 00:15:00 UTC
Last modified on: 01/24/2023 19:29:00 UTC