Shostack + Friends Blog Archive

 

The Worst User Experience In Computer Security?

I’d like to nominate Xfinity’s “walled garden” for the worst user experience in computer security.

For those not familiar, Xfinity has a “feature” called “Constant Guard” in which they monitor your internet [link to http://customer.comcast.com/help-and-support/internet/signs-your-computer-is-infected-with-a-bot/ no longer works] for (I believe) DNS and IP connections for known botnet command and control services. When they think you have a bot, you see warnings, which are inserted into your web browsing via a MITM attack.

Recently, I was visiting family, and there was, shock of all shocks, an infected machine. So I pulled out my handy-dandy FixMeStick*, and let it do its thing. It found and removed a pile of cruft. And then I went to browse the web, and still saw the warnings that the computer was infected. This is the very definition of a wicked environment, one in which feedback makes it hard to understand what’s happening. (A concept that Jay Jacobs has explicitly tied to infosec.)

So I manually removed Java, and spent time reading the long list of programs that start at boot (via Autoruns, which Xfinity links to if you can find the link), re-installed Firefox, and did a stack of other cleaning work. (Friends at browser makers: it would be nice if there was a way to forcibly remove plugins, rather than just disable them).

As someone who’s spent a great deal of time understanding malware propagation methods, I was unable to decide if my work was effective. I was unable to determine the state of the machine, because I was getting contradictory signals.

My family (including someone who’d been a professional Windows systems administrator) had spent a lot of time trying to clean that machine and get it out of the walled garden. The tools Xfinity provided did not work. They did not clean the malware from the system. Worse, the feedback Xfinity themselves provided was unclear and ambiguous (in particular, the malware in question was never named, nor was the date of the last observation available). There was no way to ask for a new scan of the machine. That may make some narrow technical sense, given the nature of how they’re doing detection, but that does not matter. The issue here is that a person of normal skill cannot follow their advice and clean the machine. Even a person with some skill may be unable to see if their work is effective. (I spent a good hour reading through what runs at startup via Autoruns).

I understand the goals of these walled garden programs. But the folks running them need to invest in talking to the people in the gardens, and understand why they’re not getting out. There’s good reasons for those failures, and we need to study the failures and address those reasons.

Until then, I’m interested in hearing if there’s a worse user experience in computer security than being told your recently cleaned machine is still dirty.

* Disclaimer: FixMeStick was founded by friends who I met at Zero-Knowledge Systems, and I think that they refunded my order. So I may be biased.