If, like me, you travel a lot, listen up—the Los Angeles District Attorney’s Office has issued an advisory as part of its fraud education campaign warning travelers not to use free USB charging stations offered in airports, hotels and other public places. 

According to the warning, “juice jacking” occurs when hackers have loaded malware into the free USB charging stations or plugs connected to a public charging station, so that when a traveler plugs in their phone, the phone is infected with malware, allowing the hacker to lock the phone, hold it as hostage for ransom, or forward sensitive information to the hacker.

Plugging your phone into an unknown device is not the best cyber hygiene in the first place, particularly when the charging station is in a public place easily accessible by hackers. Take the advice of the the L.A. District Attorney’s Office and think twice before plugging into a public charging station.