We’re all guilty of charging our phones, laptops, and other devices in public spaces. After all, what can you do when you’ve got no power and that’s your only option? But those USB ports, while convenient, can be a danger to your devices.
Public USB ports are convenient, but they’re more than just a charger
And no, that’s not a good thing.
Charging in public is pretty much inevitable. Be it at the mall, the airport, or at work, we’ve all done it at one point or another. But those ports are more than just a source of power, and while a lot of them are perfectly safe to use, they’re not all trustworthy by default.
Those ports are USB, which means they can act like a data connection that also happens to deliver electricity. And once you remember that, plugging your phone into a random airport port will feel a lot less secure, because if the data can travel one way, it can also travel both ways. That’s the part most of us forget.
In the same way you wouldn’t unlock your phone and hand it to a random stranger on the street, you shouldn’t assume a random public USB port is secure. If it can transfer data, it could potentially pose a harm to your device. This is why FBI Denver warned about charging your devices in public.
The scary term you’ll sometimes hear for this is “juice jacking.” This is basically the idea that a public charging setup could be tampered with to try access your data or mess with your device. This isn’t something that happens to everyone every single day, but since it can happen, it’s best to avoid it if you can.
The extra annoying part is that it’s hard to tell what USB port you’re plugging into. Sure, you can tell the difference between a USB-A and USB-C at a glance, and they do have different colors to help tell them apart, but you won’t immediately know whether the port you’re about to use is straight up charging or also data transfers.
Your devices have defenses, but they’re not failproof
They’re cautious by default, but you never know.
Now, I’m not trying to make you panic here: this isn’t a common occurrence, but that still doesn’t mean it should be ignored.
Zulfikar Ramzan, the chief scientist at Aura, told Slate: “There isn’t much evidence to show that ‘juice jacking’ is a widespread problem, but it still remains a real security threat.”
Fortunately, this threat is made less significant because your phone is most likely protected against it, at least to some extent—but that still depends on the device.
Phones are possibly the ones with the most guards that protect them against juice jacking, and that’s because they’re by far the most likely to be charged in all kinds of random places. iPhones have a built-in defense mechanism in that the phone will usually ask you before it shares data, and you’ll have to agree to the prompt. Without it, the phone will only accept power but no data.
Android is similar. If you plug your Android phone into something that can do data, such as a PC, Android typically defaults to charging only and shows a USB notification. But this prompt may not always come up when you’re just plugging into an airport USB port. It’s also worth digging into the settings to make sure that USB debugging is turned off, as that’s the setting that can wreak some serious havoc if you’re unlucky with random USB ports.
Laptops rarely get charged via USB. Some people use their laptop to charge their phone (also not advisable), but laptops tend to require much more juice than a typical USB port can provide. However, they’re also much more exposed to issues in this context, especially over USB-C, because they’re designed to trust a whole ecosystem of docks and peripherals.
Can a $8 Amazon gadget solve the problem?
It can help, but it doesn’t solve everything.
Amazon is full of gadgets that claim to offer protection against juice jacking at public USB ports, such as this $9 Plugable USB data blocker. So is this thing capable of completely nullifying the problem?
Well, the concept is sound. A data blocker is basically a bouncer for your USB connection: it lets power through, but it cuts off the data lines. That should eliminate the issue of your phone or your laptop coincidentally gathering malicious data.
However, even without having tested it myself, I can still say that it’s not some sort of a magic shield. It should block data transfers, which is the main problem here, but it’s more of an added layer of security than a universal solution.
These data blockers are usually affordable, though. The Plugable unit I mentioned is $9, but they’re all in the ballpark of $5 to $25. It’s a low-risk extra bit of protection against public USB ports.
Keep in mind, though, that there’s no guarantee what these cheap little adapters will do to your charging speeds. Check for fast charging capabilities and exact voltages to know whether you can trust them to give your device enough power or not.
The safer ways to charge in public
The safest way is boring and predictable, and that’s exactly what you want.
I’m not here to tell you that you should never charge your devices in public. All I’m saying is that it helps to be mindful of the dangers that could potentially lurk in unknown USB ports.
The best defense is to simply carry your own power bank and not rely on external sources of power. Otherwise, use an AC adapter and bring your own charger instead of just a USB cable.
If you do find yourself in a pinch, it doesn’t hurt to try one of those USB juice jacking blockers. Make sure that you’re also using your own cable.
Some places are incredibly low-risk when it comes to something ever happening over a public USB port, so there’s no need to become paranoid. But public areas like airports are easy pickings, so it’s always better to be safe than sorry.
