Malware isnt just something you download from the internet, or find attached to an email, or even discover lurking on a CD. Any time you plug a storage device into your computer you are potentially exposing it to any malicious code which might reside on the unit. So, that means that you have to be conscious that all sorts of items can carry malware. It doesn’t matter if its an iPod, a BlackBerry, a sat-nav, or a digital photo frame, it can transmit it to your laptop or desktop computer.”]
Source: https://grahamcluley.com/bad-bunny-energizer-usb-battery-charger-blamed-backdoor/