USB  Flash Drives

A typical USB Flash Drive

USB Flash Drives (also called thumb drives, memory sticks [not to be confused with Sony Memory Stick], pen drives, and jump drives) are similar to memory cards but plug into USB sockets. They come in many aesthetic styles in addition to the mundane example above. They are about equal in popularity to SD cards.

Like memory cards, they appear as a hard drive to the computer. Most computers can boot from flash drives, assuming the drive is formatted correctly.

Caveats:

Fake USB Flash Drives

Like fake SD cards, there are many fake USB Flash Drives on Amazon and eBay. Some fake drives are made by soldering factory reject^[1] MicroSD cards directly to the circuit board of an SC Card reader and packaging it as a USB Flash Drive. Like SD Cards, it is best not to buy SD Cards or USB Flash Drives with strange brand names.

Malware

USB Flash Drives are often infected with malware. Be wary of off-named drives on Amazon or eBay. Also, be wary of found USB Flash Drives or ones received through the mail. Cybercriminals have been known to leave infected USB Flash Drives in target company parking lots, hoping employees will connect them to company computers to see what's on them.

Typical malware on USB Flash Drives (such as BadUSB) tells the computer it is a keyboard, then types the necessary keys to install more malware over the Internet.