Inspect a USB device
To test a cable or gadget:
- With the gadget unplugged, press Pick a USB device and note what the browser’s list shows. Then press Cancel.
- Plug in the gadget. For a cable, plug only the cable into this computer, with nothing on the other end.
- Press the button again. A plain charging cable never appears. If something new shows up, the cable or gadget has electronics that talk to your computer. Pick it to see what it claims to be.
The browser only shows the details a device reports about itself, and a device can lie. Nothing is sent anywhere, and the tool does not open or change the device.
Why would a cable pretend to be a keyboard?
Because computers trust keyboards. “Computers trust keyboards because humans use them, and humans have full access to the computer” Spacehuhn: the danger of HID (read 23 Oct 2026). A device that claims to be a keyboard can type commands faster than any person.
The O.MG cable is a commercial example. Bastille describes it as “Looks like a charging cable. Works like a covert keyboard,” with an implant hidden in the connector, Wi-Fi control and, on some versions, a keylogger Bastille: the O.MG cable (1 Sep 2026).
How do I read the results?
- Vendor:Product ID is a pair of numbers the device reports. We name a few common ones; a device can copy any ID.
- Interface types say what the device can do: HID is keyboard or mouse, mass storage is a drive, audio can be a microphone, video is a camera, and a wireless controller is a radio.
- Warnings depend on what you expected. A keyboard interface is normal for a keyboard and alarming in a USB stick.
- No serial number is common in cheap devices and not a warning on its own.
What does the browser hide?
Browsers protect some devices from web pages. Chrome blocks web pages from claiming audio, HID, mass storage, smart card, video and wireless controller interfaces Web Platform Tests: WebUSB protected interface classes Chromium blink-dev: WebUSB interface class filtering (Mar 2018), and keeps a blocklist of security keys that pages cannot reach WICG: unrestricted WebUSB explainer. This tool only reads descriptors and never claims an interface, so those limits should not stop it showing a device’s details. Blocklisted security keys will not appear at all.
WebUSB works in Chrome, Edge and Opera, and Chrome on Android, but not in Firefox or Safari caniuse: WebUSB browser support (read 23 Oct 2026). We tested the tool with simulated devices; how much detail your system shows for keyboards and drives may vary. Tell us what you see.
Sources
- Bastille: the O.MG cable (1 Sep 2026)
- Spacehuhn: the danger of HID (read 23 Oct 2026)
- Web Platform Tests: WebUSB protected interface classes
- Chromium blink-dev: WebUSB interface class filtering (Mar 2018)
- WICG: unrestricted WebUSB explainer
- caniuse: WebUSB browser support (read 23 Oct 2026)
Frequently Asked Questions
How can a USB cable be dangerous?
Some cables hide a tiny computer in the plug. The O.MG cable, sold as a penetration-testing tool, looks like a normal charging cable but can act as a keyboard and type commands into your computer, and some versions have Wi-Fi. A real charging cable has no electronics that talk to the computer.
How does the inspector help?
It shows what a plugged-in device reports about itself: vendor and product IDs, maker, product name, serial number and interface types such as keyboard, storage, audio or radio. If a “charging cable” shows up at all, or a USB stick reports a keyboard interface, that is a warning sign.
Can it prove a cable is safe?
No. A device can report false names, and some implants stay quiet until they are triggered. Bastille notes that physical inspection does not reveal the O.MG implant. Treat a clean result as reassurance, not proof, and use cables you bought from a trusted source.
Why does my device not appear in the list?
Your browser hides some devices on purpose, such as security keys. A plain cable or charger has no data side, so it never appears. Some systems also show fewer details until a program opens the device.
Does it change or open the device?
No. It only reads the descriptors your browser already has. It does not open the device, send it commands or install anything.
Which browsers work?
It needs WebUSB, which Chrome, Edge and Opera offer on computers and Chrome offers on Android. Firefox, Safari and iPhones do not support it.
Next step
Worried about your phone rather than a cable? Run the Phone Stalkerware Check. For wider precautions, see the OpSec guide.