The Danger of USB Charge Points — and How to Charge Your Devices in Public Safely

by  Mose Hayward
LAST UPDATED ON  2024-04-03
PUBLISHED ON  2023-11-13

I am not a super spy, with secrets to keep. But I also don’t really want to get my devices all gunked up with the viruses that governments are using to go after each other.

I recently dove into the research on the perils of using public USB charge points in airports, trains, buses, libraries, and other locations. And now I will never use one again, at least not without the precautions described below.

The Dangers of Juice Jacking from Plugging into a Public USB Outlet

For most of the past decade — that is, as long as public USB outlets have been popping up all over — security researchers have been warning not to use them.

Documented possible lines of attack have come from multiple security experts and sources, including Symantec, Wall of Sheep at Defcon, and Krebs on Security.

Plugging into a public USB port is kind of like finding a toothbrush on the side of the road and deciding to stick it in your mouth.
Caleb Barlow, Vice President of X-Force Threat Intelligence at IBM Security, to Forbes

The researchers have demonstrated how these attacks can lead to:

  • Viruses
  • Data theft
  • Device tracking
  • Video jacking (recording what is on your screen while charging)
  • Trustjacking (allowing future access to the device via WiFi, once access is approved via the cable)

Government and business employees carrying sensitive data are regularly warned not to use public USB charge points, and also not to use others’ cables or of course USB drives found lying around.

How to Avoid Juice Jacking

The obvious remedy is simply don’t plug your device into public USB outlets. We have long recommended the devices below in any case for most travellers as they are incredibly convenient for power on the go.

Charging from Standard Public Electric Sockets is Fine

A standard wall electrical socket is the perfect alternative to the USB charge point. And the charger that came with your phone or other device is fine to use for that — just don’t use an unknown cable.

But, it is even better to have a travel adapter ready so that you can plug in anywhere and charge multiple devices at once.

It works in your home country and if you’re travelling to a country with funky juice holes, you will be prepared for any of them. There is in particular a universal power plug adapter that we recommend in our separate review of this gear, as shown below (and yes, we’ve tested out tons of them before deciding on this one).

Epicka Travel Adapter
You’ll be able to charge via three USB-C, two USB A, and one standard wall plug from a single device. It plugs into any electrical socket pretty much anywhere in the world and has overload protection and a spare fuse.

Avoid Public Charge Points Altogether by Carrying a Small Spare Battery

On trains and planes you may not have a standard plug outlet, or any outlet at all for that matter—not even the USB outlets that are the fraught subject of this article. But there’s a solution for that too; a backup battery that can fast-charge phones many times over.

If I’m going somewhere for a few days and there aren’t a lot of outlets around, I often end up just recharging my phone repeatedly from this battery and not even bothering to scrounge for an outlet. Even then, I’ll only use up half of its power. I’ve used Anker for backing up travel devices for years; the life cycle of a battery is always a bit random depending on temperatures and use, but my good experience with Anker’s reliability has been shared by other travelers and reviewers as well.

Anker 40K 30W USB-C Power Bank
Charges up to four devices simultaneously, including two USB-C devices, with a capacity of 40,000 mAh. You can fast charge via USB-C at 30W. This is more than enough speed and capacity for charging most modern phones, laptops, and such several times over and at high speed.

A Final Option If You Really Want to Use USB Charge Points: The USB “Condom”

I don’t have a need for these myself since I use the devices above, but if you want something even smaller, or really love charging at USB points, these are the protective devices for you.

PortaPow 3rd Gen USB-A Data Blocker
This plug only allows power through, and no data. Charges at up to 2.4A, so fast charging is possible if the device, cable, and charging point allow it.
PortaPow USB-C to C Data Blocker
The same thing but for USB-C charge points (which are less common still at this point).

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