How a free phone charge can lead to a hacker stealing your information

Bryan Meler
Associate Editor, Yahoo News Canada

You may have never heard the term “juice jacking” and with good reason. When it happens, most people are not even aware.

Juice jacking happens when hackers compromise a person’s device after it’s been plugged into a public charging station like the ones found at airports or malls.

Identifying potentially dangerous charging stations isn’t easy. The practice happens around the world and experts say they’ve been working on ways to prevent since at least 2012, according to Natalia Stakhanova, a Canada Research Chair who focuses on mobile security.

“Canadians should be worried, especially those who travel abroad,” says Stakhanova, who is also an associate professor in the department of computer science at the University of Saskatchewan. “Malicious chargers that comprise your information do exist.”

In 2019, Los Angeles County District Attorney's Office issued a warning against public charging stations. There have also been reports of this happening in countries in Asia, Stakhanova says.

The RCMP says they’re aware of this scamming practice, but don’t have any reported cases.

The Sûreté du Québec and the Vancouver Police Department say that they’ve had cases of identity theft, but the individuals sometimes don’t even know how the suspects got their information.

“Juice jacking” is hard to pinpoint, which makes it even more vital for you to know how to prevent it from happening.

How does it work?

The key part of this process is the USB port, which connects to a cable that can process both data and energy. It’s what allows us to transfer our information from our phones to our computers, for example. 

The USB can be infiltrated with malicious hardware, small enough to fit into your phone charger, Stakhanova says. Once hackers have done this, they can pull information or even plant a virus onto your device. 

Where should I worry?

The process of infiltrating a charging station at an airport isn’t a labour-intensive process, but it’s not simple either. These areas in airports are monitored by security 24/7. This might explain why Canada’s three major airports in Toronto, Vancouver and Montreal have reported zero cases of juice jacking happening.

But there is still a risk at public charging stations where security isn’t as strong or even among people.

“I see people sharing their devices all the time,” Stakhanova says. “They’ll plug into a stranger’s laptop for a charge, or even use their charger ... As a hacker, you can just be walking around with a malicious charger.”

Another situation to be wary of is plugging your phone into a rental car’s USB port. A hacker can infiltrate a car without the rental agency’s knowledge. 

“It’s a simplistic hacking method,” Stakhanova says. “Most of the time, the hacker just uses an existing infrastructure.” 

But what if I don’t have anything important on my phone?

Stakhanova says a common misconception is people thinking they don’t have anything that could be of use on their phones. 

But your phone can serve as a “gateway.” It can provide access to other personal aspects of your daily life, such as your email address, which can be connected to your bank account. Having access to a phone can also help hackers participate in crypto mining, as well as perform transactions when passwords, and other private information are sent to your device for verification purposes.

"You might have seen a public USB charging station at an airport or shopping centre. But be warned, a free charge could end up draining your bank account," says Luke Sisak, Los Angeles County’s deputy district attorney, in a video warning in November.

If you still think your phone doesn’t have anything important on it, remember that a hacker can steal your identity with just basic information about you, which can be found on your phone.

How can I prevent this from happening?

The key is to be more vigilant, Stakhanova says. That could mean not accepting free opportunities to charge your phone in public areas. 

Stakhanova recommends just carrying around your own AC charger.  If you do connect your phone to another device, make sure it’s blocked from transferring information.

In an email exchange with Yahoo Canada, Aéroports de Montréal says users can also look into devices that will help prevent their information from being shared. One item to consider is a USB charge-only adapter, which won’t allow your phone to share and transfer data to another device.