When cybersecurity professionals talk about patch management, they’re often thinking in terms of servers and software. But in the world of inverter-based resources (IBRs) — the solar, battery, and wind systems that are rapidly reshaping our grid — firmware is the real frontline. And here’s the catch: you can’t patch your way out of this problem.
As DERs and IBRs scale across the energy landscape, they’re bringing with them thousands of embedded systems. Most of these are governed by firmware that doesn’t follow the same rules, expectations, or update cycles as traditional IT systems. And many of these devices will live on the grid for 15–20 years, far longer than the average lifecycle of a security patch.
The Hidden Risks Lurking in Firmware
Firmware may be invisible to most operators, but it’s where some of the most critical security gaps in IBR systems live. Unlike standard IT software, firmware is deeply embedded, rarely updated, and often not monitored at all. That makes it a prime target — and a silent liability.
Over the past few years, multiple CISA ICS Advisories have flagged vulnerabilities in DER-adjacent technologies — from solar inverters to battery controllers to industrial gateway devices. These flaws range from unauthenticated access and remote code execution to unencrypted firmware update channels and hardcoded credentials. The trend isn’t limited to one product or vendor — it’s systemic.
Security researchers have also raised alarms about the lack of basic protections in many DER firmware platforms. In some cases, they’ve demonstrated how a compromised cloud management portal could be used to push malicious firmware to entire fleets of inverters, potentially disrupting generation or hiding malicious behavior.
More troubling is the vendor landscape. Many DER devices are manufactured by companies without formal vulnerability disclosure programs. Some vendors have stopped issuing firmware updates for in-use models or rely on field techs to perform manual updates, meaning many devices remain vulnerable for years. As one advisory put it bluntly: “No update is planned because the product is no longer supported.”
Experts have also warned that the firmware supply chain — especially in products sourced internationally — remains a blind spot. The code running inside your inverters may have been compiled years ago by a subcontractor and include outdated libraries with known CVEs.
And while no “SolarWinds-style” firmware-level attack has yet been made public in the DER space, the possibility is real. Embedded devices with remote connectivity, no encryption, and no patching mechanism? That’s not theoretical — it’s a recipe for grid instability.
Why Traditional Patch Management Falls Short
Patch management assumes a few things: you can remotely push updates, validate that updates were applied, and have your assets follow a predictable refresh cycle.
None of those assumptions hold true in most IBR environments.
- Vendor Lock-In: IBRs often come with proprietary platforms that restrict firmware access. Even when vulnerabilities are known, operators must wait for the vendor, and that wait can be indefinite.
- Limited Remote Update Capability: Many DER assets are installed in the field, on legacy communication links (e.g., serial modems or unsecured Wi-Fi), without secure or scalable update mechanisms.
- Downtime Constraints: Even when patches are available, taking inverters offline for updates may not be operationally feasible, especially during peak generation or demand response windows.
- Lack of Firmware Visibility: Few utilities or aggregators maintain centralized awareness of what firmware versions are running across their IBR fleet. Even fewer can verify their integrity.
In short, IBR firmware is often invisible, unmanaged, and vulnerable — a dangerous combination for critical infrastructure.
Firmware Lifecycle Security: Beyond the Patch
What’s needed is a shift in mindset: from occasional patching to firmware lifecycle management. This means treating IBR firmware as a first-class security concern, from procurement to retirement.
Here’s how leading organizations are doing it:
1. Track Software Bills of Materials (SBOMs)
Know what’s inside your inverters. Push vendors to disclose SBOMs that list firmware components and third-party libraries. This is especially critical for identifying inherited vulnerabilities when new CVEs are published.
2. Enforce Firmware Integrity Monitoring
Deploy solutions that can monitor firmware hashes, detect tampering, and alert on version drift across fleets. Firmware that changes without a logged update is a red flag.
3. Establish Vendor Risk Profiles
Rate vendors not just by performance or price but by their patch responsiveness, updated delivery model, and security architecture. Include firmware support SLAs in your procurement terms.
4. Require Third-Party Security Testing
Don’t rely on vendor self-assessments. Commission or require independent testing of firmware (and update processes) for critical DER devices, particularly before bulk deployment.
5. Plan for End-of-Support Contingencies
Every IBR asset has a sunset date, but attackers don’t care if your vendor has moved on. Establish plans to isolate, retire, or replace devices once firmware support ceases.
Time to Rethink the Inverter Security Stack
The old saying in security is “you can’t protect what you can’t see.” For IBRs, the firmware is often out of sight and out of scope, even though it directly governs power output, communication with SCADA, and interaction with aggregator platforms.
Grid operators and DER aggregators must treat firmware not as a line item on a checklist, but as an active and ongoing cybersecurity responsibility. That means shifting from reactive patching to proactive lifecycle oversight. It means asking harder questions during procurement and ensuring field teams have the tools to detect and manage firmware risks. And it means recognizing that as IBRs grow, so does the risk — and so must our commitment to securing them.
Because on today’s grid, every line of embedded code matters. And when it comes to firmware, “set it and forget it” is no longer an option.