HARRISBURG (TNS) — It’s a common sight to see passengers plugging into the free USB power ports and charging their phones when passing through an airport.

Even though a free charge comes at a much-needed time for on-the-go traveler, the Transportation Security Administration is warning the public about the common activity that poses as a serious security risk.

“When you’re at an airport do not plug your phone directly into a USB port,” the TSA warned in a PSA on Facebook.

That’s because hackers can “install malware” at USB ports. Known as “juice jacking” or “port jacking,” It’s a nifty new way Cybercriminals ransom someone’s phone and steal passwords when using a USB port that has been tampered with.

And the user wouldn’t know what’s happening because to them, they’re just charging their phones.

To combat the growing issue juice jackers are causing, instead of charging your phone using flight-hub charging stations, security officials are recommending travelers to bring their own “TSAcompliant power brick or battery pack” and plugging in there, according to the advisory. Warnings were also issued by the FBI, FFC and several tech experts.

There are also warnings against using free public WiFi, especially when making purchases or entering sensitive information.

According to the cybersecurity experts at Norton, unencrypted hotspots “transmit data in plain text, making them vulnerable to cybercriminals with the right tools.” “Hackers on the same network can intercept your online activities, including banking information, login credentials, and personal messages,” they wrote.