This New HDMI Gadget Can Block Malware From Reaching Your Computer

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According to the U.K.-based National Cyber Security Centre (NCSC), monitors and displays are an “attractive target” for cybercriminals. They’re everywhere in a modern business environment and they do sometimes facilitate access to sensitive or mission-critical data, especially when including various interfaces like USB hubs. As the NCSC points out, monitors can be used to “gain access to a network for espionage purposes, disruption, or financial gain.” That’s why it created SilentGlass, a small, plug-and-play HDMI gadget that stops malicious communications from being passed through HDMI and DisplayPort signals.

It’s not exactly the type of device you’ll want to install on your computer at home, unless you have a lot of unknown people plugging gear into your desktop or laptop. But it’s a solid option for public computers, high-security environments, and those in commercial spaces — like a computer tucked away in a back office that anyone could have access to. The NCSC says that the device has already been deployed on U.K. government estates. Now, it will be available to anyone, but perhaps most useful to those in “high-threat environments.”

Technically, the device is not ready for purchase globally just yet. The NCSC partnered with Goldilock Labs, a U.K. cybersecurity firm, and Sony UK Technology Centre to distribute the product, but buy links are not yet live as of this writing.

Some are questioning the need for a device like SilentGlass. Cybersecurity expert Scott McGready called it out on X, asking “Can anyone genuinely tell me what risk this is addressing, or is it a solution in search of a problem?”

Doing a deep dive into the potential for a display-oriented cyberattack, there doesn’t seem to be any high-profile or public examples of this sort of thing happening. At least not directly. Though, there is still a precedent. A known attack called PIXHELL that exploits LCD screen noise to exfiltrate sensitive data was discovered. Similar methods were outlined in a research paper, showing brightness levels could be changed to steal data. However, both of these methods take advantage of air-gapped computers, not their display port technologies. 

Elsewhere, an FIU research team is studying how to detect potential HDMI cyberattacks. Another research team discovered a new AI model can use leaking HDMI signals to intercept and decode on-screen content. It works by intercepting the electromagnetic radiation leaking from the HDMI cable used between a computer and monitor. The National Security Agency (NSA) calls these kinds of intrusions Tempest attacks.

That said, this is not likely to be something the average household would need to worry about. Expensive technology and complicated techniques are needed to make it work. Most people should be more concerned about something like a modded Amazon Fire TV Stick which can put your entire home network at risk. In addition, there are more relevant privacy gadgets you can rely on to protect your personal data and accounts. You’d be better off spending your money on those.

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Cyber threats are growing year after year, and AI is accelerating that problem. Between March 2024 and February 2025, cyberattacks cost U.S. companies over $10 million. New threats are also appearing, with attacks that can steal accounts and passwords despite 2FA protection. So, it’s not a surprise that security experts would want to get ahead of potential vulnerabilities, and another attack vector that can be leveraged by nefarious parties, before it becomes a bigger threat.

SilentGlass can be valuable for large corporations, government entities, and defense companies dealing with trade secrets and highly classified information. Stephen Kines, the co-founder of Goldilock Labs — the company partnering with the NCSC to distribute SilentGlass — explains that this is the “first step in a wider effort.” The goal is to “enforce behavior at hardware interfaces before it reaches complex software.” He also explains it represents a new paradigm shift of sorts “toward treating physical connectivity as a point of control rather than an assumed trust boundary.”

Previous data shows that more than half of annual malware attacks were designed with USB devices in mind, meaning they had to be physically plugged into systems to kickstart an attack. If USB is such a heavy focus for malware, it is possible other vulnerable ports could become a bigger focus, as well.