In today's fast-paced, technology-driven world, it's hard to imagine going a day without your mobile phone. That's why public charging stations at airports, hotels, and shopping centers can be a lifesaver when you're on the go. But did you know that connecting to an unfamiliar USB charging port can also pose a cybersecurity risk?
What is Juice Jacking?
"Juice jacking" refers to an attack in which a compromised USB charging port or cable is used to try to steal data or install malware on a connected device. USB connections can carry data as well as power, which creates a potential route for an attack. The Michigan Attorney General's consumer alert describes this risk and offers precautions. That doesn't mean every public charger is malicious or that plugging in automatically gives someone access to your iPhone.
Understanding the Threat
Juice jacking was already the subject of public safety advice before this article's original publication on April 17, 2023. For example, the U.S. Army Cyber Command published precautions in April 2022. These warnings describe a potential risk; they do not establish that incidents increased as COVID-19 travel restrictions eased.
Today's iPhones also have built-in protections. Apple explains that, by default, you must unlock your iPhone before it connects to a wired accessory or computer. An accessory can remain connected after the phone is locked again, so simply relocking isn't the same as disconnecting it.
Protecting Yourself from Juice Jacking
- Carry your own portable battery charger: A personal power bank can keep your phone charged without relying on public USB stations. This is one of the precautions recommended by the Michigan Attorney General.
- Use a USB data blocker: These adapters are designed to allow charging without connecting the USB data-transfer pins. The Michigan Attorney General recommends them as a precaution, but don't treat one as a guarantee of device security.
- Plug into wall sockets: Use your own power adapter and charging cable with an AC wall outlet rather than connecting directly to an unfamiliar public USB port. This follows official consumer-protection advice.
- Check your iPhone's accessory settings: In Apple's current instructions, go to Settings > Privacy & Security > Wired Accessories. On USB-C models, Always Ask requires approval for every accessory connection. Lightning models have different options. Consult Apple's model-specific guidance, and avoid enabling Always Allow just to use an unfamiliar charger.
- Don't approve unfamiliar data connections: If an unfamiliar charging connection triggers a Trust This Computer alert, tap Don't Trust. Apple says this blocks that computer's access to content on your device. If you're uncomfortable with the connection, unplug and use your own charger or power bank instead.
These simple precautions can help reduce exposure to potentially malicious USB connections, without assuming every public charger is dangerous. Stay cyber smart!