Running out of battery while travelling can be frustrating. When you spot a free USB charging port at an airport, railway station, hotel, café or other public place, plugging in your smartphone may seem like the easiest solution. But an unknown USB connection can potentially create a security risk if the charging setup has been tampered with.

The concern is often described as “juice jacking”—a scenario in which a compromised USB connection could potentially be used to access data or interact with a connected device.

This doesn't mean every public charging point is dangerous. Still, understanding how USB connections work can help you charge your phone more safely.

Why Can a USB Charging Port Be a Security Risk?

A USB cable isn't necessarily used only for electricity. Depending on the cable, port and device settings, the same connection may also support data transfer.

This is what makes an unfamiliar USB port different from plugging your own charger into a standard electrical socket.

If a charging station or cable has been maliciously modified, connecting your phone could potentially expose it to unwanted data communication.

Modern smartphones include several protections against unauthorized access, but users should still be cautious when connecting their devices to unfamiliar equipment.

Never Approve an Unexpected Data-Access Request

When you connect your phone to a USB port, you may see options related to charging, file transfer, photos or trusting a connected device.

If your only intention is to charge the phone, avoid approving requests for file transfer, data access or device trust unless you know exactly what you're connecting to.

If an unexpected permission request appears after plugging into a public charging point, disconnecting the phone may be the safer choice.

Your Own Charger Is a Better Option

One simple precaution is to carry your own charging adapter and cable.

Instead of connecting directly to a public USB