Modern substations, energy grids, and industrial automation platforms all rely on one quiet, aging protocol to keep things running: Manufacturing Message Specification (MMS).

You'll find MMS deep in the heart of IEC 61850, powering communications in substations, SCADA systems, and DCS platforms.

But here's the dangerous part:

MMS was never built with cybersecurity in mind.

And attackers are taking full advantage.

🧠 What Is MMS and Why Does It Matter?

MMS is a protocol used to:

• Exchange real-time data, control commands, and device diagnostics
• Communicate between Intelligent Electronic Devices (IEDs)
• Operate across utility, electrical, and automation sectors
• Run over TCP port 102
• Serve as a foundational piece of the IEC 61850 standard

If you're operating in energy, power distribution, or industrial automation, there's a strong chance MMS is running somewhere in your environment.

🚨 The Security Problem with MMS

Despite its critical role in industrial control systems (ICS), MMS has zero native security features.

Here's what that means in practice:

❌ No encryption ❌ No authentication 📡 All data and commands are sent in plaintext 🕵️ Susceptible to spoofing and Man-in-the-Middle (MitM) attacks 💥 Open to Denial of Service (DoS) and disruption of critical infrastructure

These aren't just theoretical risks. Threat actors are already exploiting these vulnerabilities in the wild.

🌍 What the Data Shows (Censys Research)

Using Censys, I identified:

• 🔎 15,000+ internet-exposed MMS-enabled endpoints
• 📍 Majority located in Japan and the United States
• ⚠️ Over 6,500 tied to known exploited vulnerabilities (CVE-mapped)

This means a significant portion of critical infrastructure is sitting wide open — accessible to anyone with a scanner and bad intentions.

🛡 How to Secure MMS Today

MMS may be insecure by design — but that doesn't mean you're powerless. Here's how to reduce your risk:

1. Keep MMS traffic inside the OT network ➤ Airgap where possible and segregate it from IT networks.
2. Block all external access to TCP port 102 ➤ If it's reachable from the internet, you're already at risk.
3. Deploy IEC 61850-aware firewalls & Deep Packet Inspection (DPI) ➤ Generic firewalls won't cut it.
4. Use Zeek, Snort, or Suricata to monitor MMS traffic ➤ Behavioral anomalies often precede active compromise.
5. Enforce VPN + MFA for any remote access ➤ Reduce the risk of credential stuffing or session hijacking.
6. Follow industrial standards like IEC 62443 and NIST 800–82 ➤ These frameworks provide baseline controls for ICS/OT environments.

⚡ TL; DR — MMS: Critical but Exposed

MMS is a legacy protocol designed for availability, not security.

But it's still core to how we operate substations, control electrical systems, and manage industrial automation.

If you're using it — protect it like your grid depends on it.

Because it absolutely does.

💬 Let's Talk

Are you seeing MMS in your environment? Ever audited port 102 exposure? Drop your thoughts or questions in the comments — I'd love to hear from folks in the field.

🛠️ Stay safe. Stay patched. Stay curious. Support Palestine.

This research part of oaps_another_attack_surface series, another interesting blog about industrial exposed: MMS And you found me LinkedIn