A critical vulnerability, tracked as CVE-2022-45047, has been discovered in Apache MINA SSHD (versions <= 2.9.1). The vulnerability affects the org.apache.sshd.server.keyprovider.SimpleGeneratorHostKeyProvider class, which is responsible for handling the loading of SSH host keys in various implementations. This post aims to provide an in-depth analysis of the vulnerability, its possible exploitation vectors, and how to address the security issue.

Vulnerability Details

At its core, the vulnerability lies in the deserialization process of the java.security.PrivateKey object by the SimpleGeneratorHostKeyProvider class. Apache MINA SSHD uses Java deserialization to load the serialized PrivateKey object. This functionality provides an opportunity for attackers to exploit this vulnerability for remote code execution (RCE) on affected systems.

Here's a snippet of the vulnerable code in the SimpleGeneratorHostKeyProvider class

private void loadKeys() {
    ObjectInputStream ois = null;
    try {
        ois = new ObjectInputStream(new FileInputStream(path.toFile()));
        keyPair = (KeyPair) ois.readObject();
    } catch (FileNotFoundException e) {
    } catch (ClassNotFoundException | IOException e) {
        throw new RuntimeException("Unable to read key pair, reason: " + e.getMessage(), e);

As shown in the snippet, the loadKeys method uses the ObjectInputStream class to read the serialized PrivateKey object from the provided file. The vulnerability arises from the lack of proper validation or filtering of maliciously crafted objects during the deserialization process.

Exploit Details

To exploit this vulnerability, an attacker would need to craft a malicious object that, when deserialized, would execute arbitrary code on the victim's system. For instance, using deserialization vulnerabilities, an attacker might leverage Java gadget chains. These gadget chains, when combined, can build a payload that achieves code execution during deserialization.

Once the malicious payload is crafted, the attacker would need to replace the legitimate PrivateKey object with the malicious one. Subsequently, when the SimpleGeneratorHostKeyProvider processes this modified object, it will execute the malicious code, leading to remote code execution.

Mitigation and Remediation

To address this vulnerability, developers are advised to upgrade to Apache MINA SSHD version 2.9.2 or later, which addresses this issue. The patch implemented in the updated version removes the use of Java deserialization for loading the serialized PrivateKey object, thus mitigating the risk of remote code execution through deserialization vulnerabilities.

It is also essential to follow the best practices for secure deserialization, which include

1. Use a secure deserialization library or mechanism that incorporates validation and filtering of deserialized objects.

For more information about this vulnerability, consult the following resources

- CVE-2022-45047 Entry on NVD
- Apache MINA SSHD Official Website
- Apache MINA SSHD GitHub Repository


The CVE-2022-45047 vulnerability in the Apache MINA SSHD presents a severe risk of remote code execution attacks through the exploitation of deserialization in the SimpleGeneratorHostKeyProvider class. Developers must ensure that they are using the latest version of the Apache MINA SSHD and adhere to established security best practices to mitigate the risks associated with this vulnerability.


Published on: 11/16/2022 09:15:00 UTC
Last modified on: 11/18/2022 18:09:00 UTC