Juice jacking is a security concern associated with charging a phone or other device from a public USB port or a cable of unknown origin, such as those sometimes found at airports, cafes or on shared charging stations. Because a standard USB connector carries both power and data lines, a compromised port or cable could, in theory, attempt to access data or install malware while a device believes it is only charging.
Modern phone operating systems generally ask for confirmation before allowing data access over USB, which reduces the practical risk considerably, but caution with unfamiliar charging equipment in public places remains a reasonable habit, particularly when travelling.
A simple, low cost precaution is a USB data blocker, a small adapter that physically allows only the power lines through, or using a trusted charger and cable of one's own. See our USB security guide for more on staying safe with USB.
