Technology in terms you understand. Sign up for the Confident Computing newsletter for weekly solutions to make your life easier. Click here and get The Ask Leo! Guide to Staying Safe on the Internet — FREE Edition as my thank you for subscribing!

Is “Juice Jacking” Real?

Headlines don’t always make it so.

The FBI released a warning against "juice jacking", but is it really something you need to worry about?

Charging Station

Scary news headlines abounded in recent weeks as the FBI warned against something called “juice jacking”.

Is it really a threat?

No. Not really.

Well, OK, maybe. But that’s a really really big maybe.

Become a Patron of Ask Leo! and go ad-free!


Juice jacking

While theoretically possible, “juice jacking”, or the malicious transfer of data while connected to an unknown USB charging port, is both rare and easily thwarted. Most current mobile devices won’t even allow data connections by default, and using a wall charger or USB data blocker also neutralizes the threat.

The warning

The Denver office of the FBI posted a warning on Twitter.

FBI Warning on Twitter
FBI warning on Twitter. (Screenshot:

“Avoid using free charging stations in airports, hotels or shopping centers. Bad actors have figured out ways to use public USB ports to introduce malware and monitoring software onto devices. Carry your own charger and USB cord and use an electrical outlet instead.”

The implied threat is that charging your device at a randomly available USB socket could result in malware making its way to your device.

The tech

Your USB connection is used for two separate functions:

  • Power and recharging
  • Data transfer, such as to or from your computer

It’s the latter item that is of concern. The concept is that a random socket of unknown origin offering the first could also be used to do the second maliciously. In other words, it could be used to surreptitiously copy your data from your phone or transfer malware to your phone.

It’s referred to as “juice jacking” because they’re supposedly hacking your data while you’re “juicing” (charging) your device.

But are they really?

The reality

This might have been a threat once upon a time, but today’s devices are smarter than that.

To begin with, most require an additional step for data transfer. By default, the device ignores all data, connecting only to power up. You need to take an additional, manual1 step to enable data transfer each time you want it.

Android USB Connection State.
Android USB connection state. Click for larger image. (Screenshot:

The other reality? To the best of my knowledge, there have been zero reports of juice jacking ever happening.

The protection

There’s no harm in protecting yourself, particularly since it’s easy. There are two approaches.

Use a wall charger2. Anything that plugs into a power outlet is safe to use to charge your device. There’s no data involved.

Safely charging using a wall socket.
Safely charging using a wall socket. Click for larger image. (Image:

The other approach is to use what’s called a “USB data blocker3.

A USB Data Blocker
A USB data blocker. Click for larger image.

These devices connect only the power connections between your cable and untrusted USB sockets. The data lines never make contact.

Do this

Travel safely. Honestly, I don’t want to worry about this for the reasons I’ve mentioned above, but if you like, using the solutions listed will keep you safe.

Perhaps the biggest takeaway here is not to let headlines scare you — even, apparently, if they come from the FBI.

Want something you can believe? Subscribe to Confident Computing! Less frustration and more confidence, solutions, answers, and tips in your inbox every week.

Podcast audio


Footnotes & References

1: And even somewhat cumbersome, at least on Android.

2: If you can find one. These are often at a premium in busy airports and similar locations.

3: AKA “USB condom”.

7 comments on “Is “Juice Jacking” Real?”

  1. If you have a phone or tablet that doesn’t default to charging only (all phones and tablets probably default to charging only nowadays) and you don’t want to get a USB condom, you can use a power bank in between the phone or tablet.

  2. If you have a phone or tablet that doesn’t default to charging only…

    My Amazon Fire uses a really old version of Android; I don’t believe it has any such default.

    On the other hand, I’ve never had any occasion to plug into a foreign or wayward USB port.

    Still, looking into a USB Data Blocker (I refuse to use that other term!) isn’t a bad idea…

  3. re: blocking. Reading the product description says that (paraphrased) it is useful for when the power draw of the connected device causes unintended consequences, for applications such as Raspberry Pi and similar microdevices. It also says that it won’t pass data for iPhones and smart pads that require the power connection, which are most of the devices I’d expect to be connecting to an on-the-go kiosk.


Leave a reply:

Before commenting please:

  • Read the article.
  • Comment on the article.
  • No personal information.
  • No spam.

Comments violating those rules will be removed. Comments that don't add value will be removed, including off-topic or content-free comments, or comments that look even a little bit like spam. All comments containing links and certain keywords will be moderated before publication.

I want comments to be valuable for everyone, including those who come later and take the time to read.