Here’s part of what MSFT's
Microsoft’s Software as a Service (SaaS): An Enterprise Perspective 2006 whitepaper by Gianpaolo Carraro and Fred Chong has to say about SAS 70: "SAS 70 is not a law, but auditing and disclosure standards in various jurisdictions around the world (such as Sarbanes-Oxley in the United States) make up-to-date SAS 70 reports a
de facto requirement for any business that provides services to other businesses, and any SaaS provider should consider having one readily available for examination."
Amazon published Amazon Web Services: Overview of Security Processes on 9/5/2008, which contains the following statement regarding SAS 70 audits: "AWS is working with a public accounting firm to ensure continued Sarbanes Oxley (SOX) compliance and attain certifications such as recurring Statement on Auditing Standards No. 70: Service Organizations, Type II (SAS70 Type II) certification. These certifications provide outside affirmation that AWS has established adequate internal controls and that those controls are operating efficiently."
(Cross-referenced in the Windows Azure forum).
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