Original URL: http://www.theregister.co.uk/2009/03/12/cloud_computing_dark_side/

Multi-site bug exposes cloud computing's dark lining

One vuln fits all

By Dan Goodin

Posted in Security, 12th March 2009 18:04 GMT

More dark linings have been exposed in the cloud computing craze, this time by web security expert Russ McRee, who demonstrates how a flaw in a single provider can spell trouble for numerous customers it serves.

In this case, the provider is software-as-a-service, or SaaS, provider Baynote, which offers search and other online services for technology, ecommerce, and other types of websites. After McRee discovered an XSS, or cross-site scripting error, in a Baynote feature known as Social Search, he had all he needed to carry out attacks on a wide swath of the customers who used it.

The bug made exploitation the electronic equivalent of a paint-by-numbers exercise with http://[Insert customer here].com/socialsearch/query?cn=[customer]&cc=us&q= as the template. LSI Corporation, a maker of host bus adapters and other electronics, and data management provider NetApp, were just two of the Baynote customers who were made vulnerable, according to this video.

McRee stresses that Baynote "was responsive and fixed the issue quickly." But his discovery points out a potential Achilles Heel of cloud computing: An oversight by a single vendor creates a single point of failure that can have devastating effects on an untold number of its customers.

"Should that SaaS vendor have just one chink in their armor, perhaps a web application flaw, a lapse in network security, or a physical security indiscretion, its clients and their customers all share the same risk," he writes here. "An enterprise is only as strong as its weakest link, and if someone else is managing that link for you, you have some questions to ask before marrying your business to theirs."

This isn't the first time businesses have been warned about putting too many eggs in one basket. A Salesforce.com outage in January that left more than 900,000 customers without access to crucial data also demonstrates the risks of relying on a single provider.

It's not that cloud computing is automatically a bad idea, since outages and security flaws happen in-house too. Rather, SaaS can't be viewed as a panacea and due care must be taken to assess a provider's safety. Or, as McRee puts it: "Quite simply, SaaS vendors should be held to higher standards than traditional product providers." ®