Amazon has still not provided any useful information or insights into the DDoS attack that took down swathes of websites last week, so let’s turn to others that were watching.
One such company is digital monitoring firm Catchpoint, which sent us its analysis of the attack in which it makes two broad conclusions: that Amazon was slow in reacting to the attack, and that tardiness was likely the result of its looking in the wrong places.
Even though cloud providers go to some lengths to protect themselves, the DDoS attack shows that even a company as big as Amazon is vulnerable. Not only that but, thanks to the way that companies use cloud services these days, the attack has a knock-on impact.
“A key takeaway is the ripple effect impact when an outage happens to a third-party cloud service like S3,” Catchpoint noted.
The attack targeted Amazon’s S3 - Simple Storage Service - which provides object storage through a web interface. It did not directly target the larger Amazon Web Services (AWS) but for many companies the end result was the same: their websites fell over.
The attack was on specific domain names, with the DDoS attack flooding the DNS with phony traffic. As a result, legit users were unable to get access.
“The Amazon Route 53 DNS servers responsible for AWS S3 were not available,” Catchpoint notes. “The main site was up, but data services dependent on S3 were down.”
Amazon responded by rerouting packets through a DDoS mitigation service run by Neustar but it took hours for the company to respond. Catchpoint says its first indications that something was up came five hours before Amazon seemingly noticed, saying it saw "anomalies" that it says should have served as early warnings signs.
When it had resolved the issue, Amazon said the attack happened “between 1030 and 1830 PST,” but Catchpoint’s system shows highly unusual activity from 0530. We should point out that Catchpoint sells monitoring services for a living so it has plenty of reasons to highlight its system’s efficacy, but that said, assuming the graphic we were given [PDF] is accurate - and we have double-checked with Catchpoint - it does appear that Amazon was slow to recognize the threat.
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Catchpoint says the problem is that Amazon - and many other organizations - are using an “old” way of measuring what’s going on. They monitor their own systems rather than the impact on users.
“It is critical to primarily focus on the end-user,” Catchpoint argues. “In this case, if you were just monitoring S3, you would have missed the problem (perhaps, being alerted first by frustrated users).”
It also advised Amazon (and others): "Don’t monitor your third-party cloud elements only from the cloud, especially not from the same cloud provider hosting that third party." And added: "Particularly for DNS, closely monitor availability, latency and performance with frequent tests."
In other words, Amazon missed the attack because from its perspective everything was working fine. Had it been watching the impact on its users, it might have noticed the DDoS attack sooner and so been able to react faster, limiting its effectiveness.
We’ve given Amazon several days to respond to the specific timing issue and the broader attack and will update this story if they get back. ®