Earlier this month Microsoft announced that its Office 365 subscribers would be able to upload an unlimited amount of data into Microsoft’s cloud-based infrastructure. Microsoft notes that the unlimited data storage capacity is:

just one small part of our broader promise to deliver a single experience across work and life that helps people store, sync, share, and collaborate on all the files that are important to them, all while meeting the security and compliance needs of even the most stringent organizations.

Previously, subscribers could store up to 1TB of data in OneDrive. The new, unlimited storage model, creates new potential uses of the Microsoft cloud including even “wholesale backup of their computer hard drives, or even of their local backup drives”. And, given OneDrive’s integration with contemporary Windows operating systems there is the opportunity for individuals to expand what they store to the Cloud so it can be accessed on other devices.

While the expanded storage space may be useful to some individuals and organizations, it’s important to question Microsoft’s assertion that OneDrive meets the most stringent organization’s security and compliance needs. One reason to question these assertions arise out of a memo that was disclosed by National Security Agency (NSA) whistleblower Edward Snowden. The memo revealed that:

As summarized by the Electronic Frontier Foundation, Section 702 of the FISA Amendments Act which is mentioned in the NSA memo is extremely permissive. The section has been used to authorize:

• collection of Americans’ phone records without a warrant;
• access to large portions of Internet traffic that moves through American servers;
• disclosure of collected information to other parties (e.g. the Drug Enforcement Agency);

European policy analysts agree that Section 702 is overly permissive(.pdf) and argue that the definitions used in the section are so general that “any data of assistance to US foreign policy is eligible, including expressly political surveillance over ordinary lawful democratic activities.” The scope of surveillance was made worse as a result of the FISA Amendments Act 2008. While the FAA 2008 is perhaps best known for providing legal immunity to companies which participated in the warrantless wiretapping scandal, it also expanded the scope of NSA surveillance. Specifically:

[b]y introducing “remote computing services” (a term defined in ECPA 1986 dealing with law enforcement access to stored communications), the scope was dramatically widened communications and telephony to include Cloud computing (.pdf source).

Microsoft’s expansion of OneDrive storage limits is meant to enhance its existing consumer cloud offerings. And such cloud storage can produce workplace efficiencies by simplifying access to documents, protecting against device loss, and externalizing some security-related challenges.

However, if subscribers take advantage of the new unlimited storage and send ever-increasing amounts of data into Microsoft’s cloud, then there will be a much greater amount of information that is readily available to the NSA (and other allied SIGINT agencies). And given that Section 702 authorizes surveillance of foreign political activities there is a real likelihood that data content which was previously more challenging for NSA to access will now be more readily available to interception and analysis.

Signals intelligence agencies, such as the NSA, are likely not top of mind threats to individuals around the world. However, Microsoft’s willingness to manufacture government access to personal and business data should give people pause before they generate sensitive documents, share or store intimate photos, or otherwise place important data in Microsoft’s cloud infrastructure. Any company so willing to engineer its users’ privacy out of personal and enterprise services alike must be treated with a degree of suspicion and its product announcement and security assurances with extremely high levels of skepticism.