Malware-infected USB drives are portable storage devices that contain harmful software designed to disrupt, damage, or gain unauthorized access to computer systems. These drives can spread malware when connected to a computer, often without the user's knowledge. Common types of malware include viruses, worms, and ransomware, which can lead to data loss or theft. Cybercriminals often use social engineering tactics to distribute these infected USB drives, leaving them in public places or sending them through the mail. Once someone plugs in the drive, the malware can automatically execute, compromising the security of the connected device and potentially spreading to other systems within a network.