The U.S. Cybersecurity and Infrastructure Security Agency (CISA) recently issued an advisory revealing critical flaws in EG4’s solar inverters. The weaknesses, it warned, could allow hackers to intercept data, install malicious firmware, or seize control of the system if they gained network access.
For the 55,000 homeowners with EG4 inverters, the news was unsettling. Many had never thought of their solar systems as possible targets for cyber intrusions.
From Obscure Hardware to National Security Issue
Until recently, solar inverters were viewed as simple power converters. Today, they act as the digital backbone of home energy systems, regulating supply, monitoring output, and sending excess power back to the grid. “Nobody knew what the hell a solar inverter was five years ago,” said a consultant with industrial cybersecurity firm Dragos. “Now we’re talking about them at the national and international level.”
According to the U.S. Energy Information Administration, small-scale residential solar grew more than fivefold between 2014 and 2022. Each new installation strengthens energy independence but also adds a potential entry point for hackers.
EG4 Customers Left in the Dark
Showalter insists EG4’s flaws reflect industry-wide issues, pointing to nearly 90 vulnerabilities disclosed across solar systems since 2019. Still, customers were outraged after learning that EG4’s software transmitted data in unencrypted plain text, used weak authentication, and lacked integrity checks for firmware updates.
“These were fundamental security lapses,” said one EG4 customer, who criticized the company for failing to warn owners promptly. Many first learned of the issue only after CISA went public. Showalter defended his decision, calling it a “live and learn” moment.
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A Regulatory Vacuum in Home Solar Security
Part of the problem is structural. Large-scale power facilities are covered by strict cybersecurity standards from the North American Electric Reliability Corporation (NERC). But residential systems — producing far below the 75-megawatt regulatory threshold — remain largely unregulated.
That leaves cybersecurity to the discretion of individual manufacturers. In practice, the patchwork oversight has created a vast, distributed attack surface. “If you remotely control a large enough number of home solar inverters and do something nefarious at once, that could have catastrophic implications for the grid,” warns the U.S. standards agency NIST.
Global Supply Chain and Geopolitical Tensions
The timing of EG4’s troubles coincides with mounting U.S. concerns about foreign-made energy hardware. Earlier this year, officials reportedly discovered undocumented communication devices in Chinese-made inverters and batteries. Given China’s dominance in solar manufacturing — with Huawei leading 29% of global shipments in 2022 — the risks carry global implications.
Lithuania has already banned remote Chinese access to major solar and battery systems. Showalter says EG4 is now shifting toward suppliers in Germany and elsewhere to reassure customers.
CISA’s “Trust Upgrade” and Next Steps
Despite criticism, Showalter has welcomed CISA’s oversight, calling it a “trust upgrade.” Since June, EG4 has reduced its list of vulnerabilities from 10 to three, with fixes expected by October. Steps include strengthening authentication, verifying technical support identities, and redesigning firmware protocols.
But for many customers, the episode revealed a stark reality: in adopting clean energy, they inadvertently joined a complex cybersecurity battlefield. What seemed like a green investment has now become a matter of digital resilience.