In June 2023, security experts discovered a vulnerability identified as CVE-2023-4586 affecting the Hot Rod client—a Java-based protocol used by Infinispan and other distributed cache servers. This issue is significant, especially for applications relying on encrypted TLS/SSL connections for secure data transfer. This post will break down this vulnerability, show you (with code) how it happens, and outline what you can do to stay secure.

What Is the Hot Rod Client?

The Hot Rod client is a library heavily used with Infinispan, an open-source distributed in-memory key/value data store. It's popular in Java environments, where developers need fast, scalable caching or session storage. Like many modern clients, Hot Rod supports encrypted communication via Transport Layer Security (TLS).

What’s CVE-2023-4586 About?

A vulnerability was reported and tracked under CVE-2023-4586. The problem is simple but critical: When using TLS, the Hot Rod client does not enable hostname validation.

Hostname validation is an important security check in TLS. When a client connects to a server securely (for example, my-server.com), the TLS certificate presented by the server is supposed to prove that the server is indeed my-server.com. Without validation, an attacker could present a fake certificate, and the client would accept it without complaint.

This opens the door for Man-in-the-Middle (MITM) attacks. An attacker sitting on the network could impersonate the real server, intercept and even change any data sent between the client and server.

Exploiting CVE-2023-4586: How Bad Can This Get?

Imagine an attacker in a public Wi-Fi hotspot targeting apps using Hot Rod clients with TLS. The attacker:

Intercepts the connection.

2. Presents a self-signed certificate (accepted by the Hot Rod client, because hostname validation is OFF).

Suppose you have a typical Hot Rod client setup

ConfigurationBuilder builder = new ConfigurationBuilder();
builder
    .addServer()
        .host("infinispan.example.com")
        .port(11222)
    .security()
        .ssl()
            .enable() // Enable SSL
            .trustStoreFileName("/path/to/truststore.jks")
            .trustStorePassword("password");
// Hostname validation is NOT enabled by default!
RemoteCacheManager manager = new RemoteCacheManager(builder.build());

The above code does NOT enable hostname validation and so is susceptible to MITM attacks.

How the Attack Works (MITM Walkthrough)

1. Attacker's Toolkit: The attacker uses tools like mitmproxy or Bettercap to intercept TLS connections.
2. Redirection: The client is tricked—via DNS spoofing or ARP poisoning—into connecting to the attacker's machine.

Safer Code (Mitigation)

Developers should always enforce hostname validation when using TLS.

From Hot Rod 14..7.Final and above, the library added explicit support for this.

Example of proper implementation

ConfigurationBuilder builder = new ConfigurationBuilder();
builder
    .addServer()
        .host("infinispan.example.com")
        .port(11222)
    .security()
        .ssl()
            .enable()
            .trustStoreFileName("/path/to/truststore.jks")
            .trustStorePassword("password")
            .sniHostName("infinispan.example.com")
            .hostnameValidation(true); // Critical fix!
RemoteCacheManager manager = new RemoteCacheManager(builder.build());

Always use the latest release and set hostnameValidation(true) explicitly.

- CVE-2023-4586 on NVD
- Infinispan Official Docs
- Red Hat Security Notification
- MitM Proxy Tools

Patch your libraries, double-check your TLS settings, and don’t trust defaults!

Feel free to share this post and protect your data!

Timeline

Published on: 10/04/2023 11:15:10 UTC
Last modified on: 11/10/2023 18:15:10 UTC