A critical deserialization vulnerability (CVE-2023-23638) has been identified in the widely-used open-source RPC framework, Apache Dubbo. This vulnerability allows an attacker to execute malicious code on the targeted system, leading to the potential compromise of its integrity, confidentiality, and more. This issue affects Apache Dubbo versions in the following ranges: 2.7.x version 2.7.21 and prior, 3..x version 3..13 and prior, and 3.1.x version 3.1.5 and prior.

In this post, we will delve into the details of this vulnerability, focusing on the code snippet, the original references, and the exploit-associated information.

Vulnerability Details

This vulnerability stems from the Dubbo framework's support for generic invokes. When remote procedure calls are processed, the framework deserializes the supplied object's data, making it possible for an attacker to inject malicious code or objects into the system.

The vulnerability can be exploited using a simple, specially crafted payload that leverages Java's powerful native deserialization capabilities. The payload is designed to bypass Dubbo's built-in security mechanisms, ultimately enabling the attacker to execute arbitrary code on the remote system.

Code Snippet

To better illustrate the vulnerability, let's take a look at a sample code snippet that demonstrates the issue:

public class DubboDeserializer {
    public Object deserialize(byte[] data) {
        try (ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(data);
             ObjectInputStream objectInputStream = new ObjectInputStream(byteArrayInputStream)) {
            return objectInputStream.readObject();
        } catch (IOException | ClassNotFoundException e) {
            // Error handling omitted for brevity
        }
        return null;
    }
}

In this simplified example, the deserialize method reads an object from a byte array using Java's built-in ObjectInputStream class. No safeguards or checks are in place to ensure that the object being deserialized is safe or valid, which makes it possible for an attacker to deserialize a malicious payload.

Original References

This vulnerability was first reported by security researchers and subsequently addressed by Apache Dubbo's development team. Here are some of the key references detailing this vulnerability:

Apache Dubbo's official security advisory

CVE-2023-23638: Dubbo Deserialization Vulnerability Advisory

Apache Dubbo's GitHub repository issue tracking this vulnerability

CVE-2023-23638: Deserialization Vulnerability

NIST National Vulnerability Database (NVD) entry for CVE-2023-23638

CVE-2023-23638 on NVD

Exploit Details

Although no publicly known exploits have been published, security researchers have demonstrated the potential impact of this vulnerability through proof-of-concept (PoC) exploits. Further details of these PoC exploits and their impact are not disclosed due to security concerns.

Mitigation & Recommendations

To mitigate this vulnerability, users are strongly advised to update their Apache Dubbo installations to a patched version. The following safe releases have been provided by the Dubbo development team:

Apache Dubbo 3.1.x version 3.1.6 or later

Additionally, users should follow best practices for secure deserialization, such as validating input, implementing custom deserialization methods, and applying strict access controls.

Conclusion

CVE-2023-23638 represents a significant threat to the security and integrity of systems running vulnerable versions of Apache Dubbo. By understanding this vulnerability and its potential consequences, developers and system administrators can take appropriate steps to mitigate the risks and protect their systems from malicious exploitation. Staying up-to-date with the latest security patches and following best practices for secure coding are crucial for maintaining a strong security posture.

Timeline

Published on: 03/08/2023 11:15:00 UTC
Last modified on: 03/14/2023 17:57:00 UTC