USB Snooping Made Easy: Crosstalk Leakage Attacks on USB Hubs (2017)

The Universal Serial Bus (USB) is the most prominent interface for connecting peripheral devices to computers. As such information is only sent along the communication path from the device to the computer, it was hitherto thought to be protected from potentially compromised devices outside this path. We have tested over 50 different computers and external hubs and found that over 90% of them suffer from a crosstalk leakage effect that allows malicious peripheral devices located off the communication path to capture and observe sensitive USB traffic.

Source: www.usenix.org