The risk of information leakage and the Slingbox Pro

Security is hard. Sometimes, you secure the information well enough that it is infeasible to determine what the encrypted information is, and you feel like you’ve done well. Normally, that would be enough. However, sometimes you have some clever folks come along and look at the characteristics that aren’t subject to encryption to figure out what the secured data is. Basically, an attack on the secondary information in the stream. So what, exactly, does this mean? Well, in this particular instance, I found the security and privacy analysis on gadgets extremely interesting. These researchers were able to determine with extremely high accuracy what movies were being streamed from a Slingbox Pro based on the variation in amount of data sent. They couldn’t tell what the data was, but could still count the number of bits and compare that information to known characteristics of the unencrypted streams from movies to guess what was being passed.

The Slingbox Pro is not the only target of their investigations, but it is the most interesting to me. They also find privacy issues with the Nike+iPod Sport Kit and security issues with Microsoft’s Zune social relationships.

We analyze three new consumer electronic gadgets in order to gauge the privacy and security trends in mass-market UbiComp devices. Our study of the Slingbox Pro uncovers a new information leakage vector for encrypted streaming multimedia. By exploiting properties of variable bitrate encoding schemes, we show that a passive adversary can determine with high probability the movie that a user is watching via her Slingbox, even when the Slingbox uses encryption. We experimentally evaluated our method against a database of over 100 hours of network traces for 26 distinct movies.

Despite an opportunity to provide significantly more location privacy than existing devices, like RFIDs, we find that an attacker can trivially exploit the Nike+iPod Sport Kit’s design to track users; we demonstrate this with a GoogleMaps-based distributed surveillance system. We also uncover security issues with the way Microsoft Zunes manage their social relationships.

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