Most organizations pour enormous resources into defending their digital environments. They deploy endpoint agents, enforce multifactor authentication, monitor logs, and build layered controls that make traditional data exfiltration harder every year. Yet there is a quiet and often overlooked attack surface that sits right on the desk of every employee. It is the physical path between a computer and its monitor. This is where a new class of hardware based screen scraping devices has emerged, and they are reshaping the insider threat landscape in ways many companies have not yet recognized.
The most widely known example is the Hak5 Screen Crab. Hak5 describes it as a stealthy video man in the middle implant that sits between HDMI devices to quietly capture screenshots and optionally stream them through Hak5 Cloud C2. Hacker Warehouse describes it as a covert inline screen grabber that can save full motion video or interval screenshots to a microSD card and even stream content remotely through WiFi. Lab401 calls it a highly covert HDMI interception and exfiltration device that can passively intercept any video signal and store or stream it without detection.
These are not theoretical tools. They are real products that anyone can buy, and that accessibility is exactly what makes them so concerning.
How Easy It Is to Obtain a Hardware Screen Scraper
One of the most alarming aspects of devices like the Screen Crab is how trivial they are to acquire. There are no special licensing requirements, no background checks, and no enterprise verification. They are sold openly through pentest gear shops and consumer marketplaces. Hak5 sells the Screen Crab directly on its website and ships worldwide within a few days. Hacker Warehouse lists it as an off the shelf product available for immediate purchase. Lab401 ships it from both the United States and Europe and markets it to pentesters, system administrators, and government users.
The price point is low enough that any employee could purchase one without raising suspicion. The form factor is small enough to fit in a pocket. It looks like a generic HDMI adapter. It draws power from USB, which means it can run off the USB port on the monitor itself. There is nothing exotic about it. From a defensive perspective, this means procurement controls are irrelevant. You cannot stop an insider from buying one. You can only stop them from using it.
How an Insider Could Attempt to Use a Screen Scraper
To defend against this threat, it is essential to understand how an insider might attempt to use a device like the Screen Crab. The attack chain is simple, fast, and almost entirely invisible to digital controls.
Physical Access to the Workstation
The device must be placed inline between the computer and the monitor. That means the insider needs physical access to the back of the workstation or docking station. This could happen at their own desk, in a conference room, in an executive office during cleaning or maintenance, or under the pretense of troubleshooting a display issue. Installation takes seconds. Unplug HDMI. Insert the device. Plug HDMI back in. The monitor continues to work normally.
Powering the Device
Most screen scraping implants draw power from USB. The Screen Crab uses a USB C port and requires only a standard five volt one amp power source. Many monitors provide exactly that. This allows the insider to avoid plugging anything into wall power, which reduces visibility and suspicion.
Capturing the Data
There are two primary ways an insider could use the device to capture information.
Local Storage on microSD
This is the most dangerous scenario. The device silently saves screenshots or video to a microSD card. There is no network traffic. No logs. No alerts. No endpoint agent sees anything because the operating system is not involved. The insider simply retrieves the SD card later. This bypasses nearly every digital control an enterprise has.
Wireless Exfiltration
The Screen Crab includes a WiFi module and can stream screenshots or video to Hak5 Cloud C2. This introduces wireless signals and network traffic, which makes it more detectable. Some insiders might still attempt it, but most would avoid the risk. Local storage is far stealthier.
Retrieving the Data
The insider returns later, removes the SD card or the entire device, and walks out with the captured information. Because the device captures whatever appears on the screen, it can collect emails, financial dashboards, legal documents, source code, credentials, internal tools, and executive communications. It captures the final rendered output, which is often the most sensitive form of the data.
This is why screen based exfiltration is so attractive. It bypasses file access controls, clipboard monitoring, DLP, encryption, and endpoint agents. It operates entirely outside the digital plane.
Why This Threat Is So Hard to Detect
Most organizations are not monitoring the physical path between a computer and its display. They assume the threat is digital. They assume the endpoint agent will see everything. They assume the network is the only exfiltration path worth worrying about.
Hardware screen scrapers break all of those assumptions.
They do not interact with the operating system.
They do not generate logs.
They do not require drivers.
They do not appear in device manager.
They do not show up in EDR.
They do not trigger DLP.
They do not require admin rights.
They are invisible to every digital control you have. The only way to detect them is through physical security, behavioral analytics, and environmental monitoring.
How to Defend Against Hardware Screen Scraping
Organizations need to rethink their insider threat posture. The attack surface is not just digital. It is physical, and the physical layer is often the weakest link.
Lock Down Physical Access
Secure docking stations and monitor cables. Use cable locks or enclosed mounts. Restrict unsupervised access to executive offices. Limit after hours access to sensitive areas.
Implement Visual Inspection Protocols
Conduct regular workstation audits. Train facilities and security staff to recognize inline devices. Perform randomized checks of HDMI paths.
Monitor for Rogue Peripherals
Some organizations monitor for unexpected HDMI EDID signatures or unusual USB power draw. This is not foolproof, but it raises the bar.
Harden High Risk Environments
Executives, finance, legal, research and development, and SOC analysts should not have exposed HDMI paths. Options include all in one systems, monitors with integrated compute, disabling monitor USB ports, and using tamper evident seals.
Use Behavioral Analytics
Even if the device is stealthy, the person rarely is. Look for unusual time spent near hardware, attempts to avoid cameras, badge access anomalies, repeated offers to help with technical issues, or sudden interest in cables or docks.
Insider threat is always a combination of motive, opportunity, and capability. Hardware screen scrapers reduce the technical capability barrier to almost zero. That means defenders must focus on opportunity and behavior.
Conclusion
The rise of hardware screen scraping devices is a reminder that security is not just about software. It is about people, physical environments, and the small overlooked details that create openings for insiders. These devices are legitimate tools used by pentesters and administrators, but like any tool, they can be misused. Because they operate outside the digital plane, they represent a blind spot that many organizations have not yet addressed.
If you are responsible for insider threat, executive protection, or physical security, this is a threat vector you cannot ignore. The path between a computer and its monitor is now an exfiltration channel, and it is one that traditional controls cannot see.
Sources
Hak5 Screen Crab product page. https://shop.hak5.org/products/screen-crab
Hacker Warehouse Screen Crab listing. https://hackerwarehouse.com/product/screen-crab
Lab401 Screen Crab overview. https://lab401.com/products/hak5-screen-crab
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