Readers of this blog may recall that I’m a big fan of the RSA-key ‘cracking’ research of Nadia Heninger, Zakir Durumeric, Eric Wustrow and Alex Halderman. To briefly sum it up: these researchers scanned the entire Internet, discovering nearly 30,000 weak RSA keys installed on real devices. Which they then factored.
In the fast-paced world of security, this is already yesterday’s news. The problems have been responsibly disclosed and repaired, and the manufacturers have promised not to make, well, this particular set of mistakes again. The research even received the Best Paper award at Usenix Security.** So you might ask why I’m writing about it now. And the answer is: I’m not.
What I’m writing about today is not the research itself, but rather: the blowback from the research. You see, Heninger et al. were able to conduct their work mostly thanks resources rented from Amazon’s Elastic Compute Cloud (EC2). And in response, Amazon has booted them off the service.
This is a real drag, and not just for the researchers in question.
Cloud services like EC2 are a huge resource for ethical security researchers. They help us to learn things about the Internet on a scale that we could never accomplish with the limited resources in most university labs. Cloud services also give us access to software and hardware that would be nigh on impossible to justify to a grant committee, stuff like GPU cluster instances which are invaluable to cryptographers who want to run specialized cracking tasks.
But more importantly: the rise of cloud computing has given rise to a whole new class of security threat: things we never had to worry about before, like side-channel and covert channel attacks between co-located VMs. Securing the cloud itself requires real-world analysis, and this means that researchers have to be trusted to do some careful, non-malicious work on actual platforms like EC2. Unfortunately this is just kind of research that the Heninger et al. ban could serve to discourage.
Now, I don’t pretend that I know all the details of this particular case. I haven’t spoken to the researchers about it, and although the paper makes their scan seem pretty benign, it’s always possible that it was more aggressive than it should have been.*
Moreover, I can’t challenge Amazon’s right to execute this ban. In fact their Acceptable Use Policy explicitly prescribes security scans under a section titled ‘No Security Violations’:
- Unauthorized Access. Accessing or using any System without permission, including attempting to probe, scan, or test the vulnerability of a System or to breach any security or authentication measures used by a System.
The question here is not whether Amazon can do this. It’s whether their — or anyone else’s — interests are being served by actually going through with such a ban. The tangible result of this one particular research effort is that thousands of vulnerable systems became secure. The potential result of Amazon’s ban is that millions of systems may remain insecure.
Am I saying that Amazon should let researchers run amok on their network? Absolutely not. But there has to be a balance between unfettered access and an outright ban. I think we’ll all be better off if Amazon can clearly articulate where that balance is, and provide us with a way to find it.
Update (9/3): Kenn White points me to this nice analysis of the public EC2 image-set. The authors mention that they worked closely with Amazon Security. So maybe this is a starting point.
* Admittedly, this part is a little bit ambiguous in their paper. NMAP host discovery can be somewhere between gentle poke and ‘active scrub’ depending on the options you’ve set.
** In case you haven’t seen it, you may also want to check out Nadia’s (NSFW?) Usenix/CRYPTO rump session talk.