Securing the Shadows: What Legacy Building System Vulnerabilities Teach Us About SRE and Asset Visibility

A recent report by Honeywell, highlighted by Facilities Dive, underscores a critical security blindspot for modern enterprises: legacy building systems. Facilities, HVAC, and building management systems (BMS) are increasingly connected to corporate networks but are rarely managed with the same rigorous standards as production software. This operational technology (OT) lag leaves organizations exposed to high-cost cyberattacks.

The SRE Perspective: The Danger of Unmonitored Assets

In Site Reliability Engineering (SRE), a core tenet is that visibility is the foundation of reliability and security. Legacy endpoints running on obscure subdomains represent a massive, unmonitored attack surface. If an attacker gains access to a neglected building control system, they can pivot into core corporate networks, leading to downtime, data breaches, and severe reputational damage.

Many of these legacy endpoints suffer from two common, preventable weaknesses:

1. Expired or Weak SSL/TLS Certificates: Legacy devices often run on self-signed or expired certificates, exposing communication to Man-in-the-Middle (MITM) attacks.
2. Forgotten DNS Records: Subdomains like hvac-control.company.com may point to decommissioned servers or legacy IP spaces, making them ripe for DNS hijacking.

How Rabbit SaaS Secures Your Entire Footprint

You cannot protect what you do not know exists. Rabbit SaaS provides the exact tools SRE and DevOps teams need to discover and secure these forgotten systems:

• Certificate Guardian: Automatically discover, track, and monitor SSL/TLS certificates across your entire infrastructure. Ensure that even legacy OT dashboards use modern, active certificates, preventing security vulnerabilities and browser warnings.
• Domain Audit HQ: Proactively monitor your domain names, DNS configurations, and WHOIS records. Discover dangling DNS records pointing to legacy facilities hardware and get alerted before an attacker can exploit them.

Securing your organization requires looking beyond the main application cluster. By applying continuous monitoring practices to your entire digital footprint, you turn invisible vulnerabilities into managed, resilient endpoints.