Experts recommend using 'USB condom' for charging devices in public

File photo (iamtui7/

How many times has this happened to you? You’re stuck at an airport and your cellphone battery is low. You luck out and find an open USB port at a public charging station and plug in.

Once connected, you think everything is working the way it should. But it’s not.

“The issue is that the interface you use for charging, like a USB, can also carry data,” says C. Matthew Curtin, founder and CEO of Interhack Corporation, a cybersecurity and computer expert firm based in Columbus. “So, when you are there for the purpose of getting power, you have also allowed the transfer of data and that’s where the risk comes in."

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He says hackers have for years modified USB connections in public places like airports, hotels and rental cars to install malware onto phones and download data without the owner’s knowledge.

“Remember, whenever you are making a connection — what that connection is capable of, not what it is designed to do — but what it’s capable of,” he said.

A simple fix known in the industry as “a USB condom” can prevent accidental data exchange because it cuts off the data pins in the USB cable.

car charger

“Yes, it’s a prophylactic device,” Curtin says with a straight face. “It literally stops data from flowing while allowing power to flow through.”

Curtin says this can be used anywhere you might find a USB port to charge your phone, say at an airport, hotel or inside a rental car.

Curtin says hackers are known to tamper with charging outlets, like how hackers use skimming devices at ATMs or gas station pumps.


The best prevention is, well, according to Curtin, abstinence.

“I don’t use an airport charger,” he said. “I don’t plug into USB interfaces, anywhere.”