Lonely Planet Writer

Could your smartphone be at risk when when using a public USB charger?

Picture the scene: you’re about to embark on a long journey but just before you board your bus, train or plane, you realise your smartphone or tablet is low on battery. You find a public USB port nearby and plug in your device, hoping to get enough juice to see you through your trip. It seems like a pretty straightforward thing to do but public USB ports aren’t always safe and security experts warn that they could put your phone at risk.

Man Using Mobile Phone and Charging Station at Airport
Plugging your phone into an unknown charging port puts it at risk Image by Onfokus/Getty Images

Back in 2016, researchers at security firm Kaspersky Labs found that they could install a third-party application, like a virus, onto a smartphone via its USB cable connection to a computer in under three minutes. That’s because a USB port is designed to transfer data, not just power. If it’s compromised, hackers could have unlimited access to your information, including emails, text messages, photos and contacts.

But is this still a cause for concern with newer phone models and security software updates? Chris Hoffman from How-To Geek reports that current iPhones and Android phones usually require your permission to share data so the risk is minimal. He explains that with an iPhone “you’re safe unless the charger attacks your phone through an unknown security hole.” Apple’s USB Restricted Mode, a recent security update, gives extra protection to iPhones and iPads by shutting off access to data on devices when charging via the Lightning port. He warns, however, that there are slightly bigger risks with Android models.

Current models of phones are better protected against hackers / EyeEm/ Getty Images

“Modern Android phones are designed to protect your data from malicious USB charging ports. Despite this, there have been some reports about theoretical security vulnerabilities related to AT modem commands [instructions used to control a modem], and I haven’t seen any reports they’ve been fixed,” Chris explained to Lonely Planet Travel News. “Let’s be clear, though: I haven’t seen any reports that these flaws are being exploited out there in the real world. There’s no evidence that a bad USB port has ever exploited them. Despite that, it’s always a good idea to have the latest security updates for your Android devices.”

Packing your own power block can save hassle. Image by Getty

Chris believes that the average person shouldn’t worry about this but if they want to be extra cautious, he recommends travelling with a portable power bank and charging your device from that.

“Even when you’re at an outlet, plug the power bank into the outlet and plug your phone into the power bank to charge. This will insulate your phone from a (theoretical) bad USB port. And you’ll have a portable power bank so you can charge your phone on the go, even when you’re away from an outlet.”

You could also just plug with your own charger and a standard electrical outlet. If you skip the USB charging ports, you should be fine.