USB devices are used on a daily basis around the world. Virtually every device one can think of seems to have a USB port of some sort. However, it turns out that electric signals from USB ports can expose sensitive information to an attacker who knows what he or she is looking for. This trend is known as channel-to-channel crosstalk leakage, and it can affect all types of devices.
USB Devices Can leak Sensitive Information
USB devices may not be as secure as was originally assumed. This is not because they themselves can be tampered with, but rather that the protocol used to communicate through a USB port can leave sensitive data exposed. Voltage fluctuations of a USB port’s data lines can be monitored from any other port on the same hub or controller. This gives attackers access to such information which is unknowingly shared when these fluctuations occur.
No one would think that electric signals could be used to leak data to adjacent USB ports. Unfortunately, that is exactly the case. Imagine if this happened at public locations where people freely charge their phones or tablets. A malicious actor with an active data transfer connection could potentially capture information coming from those other devices. That would be quite problematic, to say the least.
Channel-to-channel crosstalk leakage, as this is known, can have severe consequences for anyone falling victim to it. Any type of information transmitted by one’s USB device in an unencrypted form can effectively be collected by an assailant targeting a different USB port on the same hub. It requires physical access to the hub or computer in question, since this information cannot be collected through software-based modifications. That is a good thing, but it does not necessarily alleviate the concerns associated with this security risk either.
Once the information is collected from USB devices, it can then be transmitted to a centralized server. If researchers determine which server is being utilized, they can shut it down without too much of a problem. Of course, that assumes people realize someone is snooping on them through the USB protocol in the first place. In reality, it is pretty difficult to spot this type of activity, as it does not draw more power nor does it give any indication that someone is actively scanning hubs.
Executing a successful channel-to-channel crosstalk leakage attack is not all that difficult. People have a tendency of picking up random USB drives when they are handed out free of charge or accidentally left behind. Many companies use free USB drives as a marketing tool, but they could just as easily be used to lay the groundwork for attacks such as this one. Very few consumers worry about potential security repercussions when using untrusted USB devices these days, and that situation will not change anytime soon.
Considering how our society relies on USB devices more than ever before, attacks such as these could become a lot more prevalent than assumed right now. Crosstalk leakage attacks constitute a very disturbing trend among cybercrime tools, although it may prove to be rather harmless in the long run. As it happens, no one knows whether such attacks have been successful already, simply that they are certainly possible. That free USB stick you were given last week may not be as innocent as you first thought.
