What Is Juice Jacking? Are Public USB Charging Ports Safe?

Juice jacking is when a public USB charging port, or a cable left plugged into one, is used to try to reach the data on your phone instead of only giving it power. It is a risk at airports, hotels, cafes and train stations, wherever you plug into a USB port you do not own.

Checked on 7 November 2026.

How does juice jacking work?

Juice jacking works because a USB cable carries both power and data. A normal wall plug only sends power, but a USB port can also talk to your phone. A tampered charging station or a planted cable can try to start a data connection the moment you plug in. The goal is usually to copy files, install something unwanted, or get your phone to trust the device on the other end.

Is juice jacking a real risk on iPhone?

Juice jacking is a smaller risk on a modern iPhone, but not zero. When you plug an unlocked iPhone into a new computer or device that asks for data, iPhone shows a "Trust This Computer?" question, and nothing can read your files until you tap Trust and enter your passcode. The risk comes from tapping Trust by habit, or from an old phone that has not been updated. Security agencies still advise people to avoid unknown USB ports when they can.

What are the warning signs at a charging station?

The warning signs are easy to miss when your battery is low:

Your phone asks "Trust This Computer?" while plugged into a wall or kiosk port.

A cable is already hanging in the port, left by someone else.

The port or kiosk looks opened, loose or covered with stickers.

Your phone shows a data or accessory message instead of just charging.

If you see any of these, unplug and use another way to charge.

How do you charge safely in public in 4 steps?

Use your own plug. Bring your own charger and plug it into a normal power socket, not a USB port.

Never tap Trust on a charger. A charging station never needs your trust. Tap Don't Trust and unplug.

Carry a power bank. Charge it at home and use it on the go, so you never need a public port.

Keep iPhone updated. Go to Settings > General > Software Update, because updates close the gaps attackers rely on.

Does a VPN protect you from juice jacking?

No. A VPN protects the data that travels over your internet connection, such as on public Wi-Fi. Juice jacking happens through the cable itself, so the protection there is your own charger, a power bank, and never trusting an unknown device. Use both: your own plug for the battery, and a VPN for the Wi-Fi at the same airport or cafe.

Frequently asked questions

Is it safe to charge my phone at the airport?

It is safe with your own charger in a normal power socket, or with a power bank. Be careful with USB ports and cables you did not bring.

What happens if I tapped Trust by mistake?

Unplug right away. You can reset which computers your iPhone trusts in Settings > General > Transfer or Reset iPhone > Reset > Reset Location & Privacy.

Is a cable from a shop or a friend safe?

A cable from a known shop is fine. Avoid cables you find left in a port or that come from someone you do not know.

---

CasperVPN encrypts your internet connection with WireGuard, OpenVPN, IKEv2 and CasperCloak, our own protocol, on iPhone and iPad (Mac app coming). Learn more in Airport Wi-Fi safety checklist or Download CasperVPN →