Dropbox Lack of Security

I am a fan of Dropbox. It is a great tool, a great product, and clearly they have a passionate team over at Dropbox building the product.

Dropbox recently announced an update to its security terms of service in which they announced that they would provide the government with your decrypted files if requested to do so.

This is not my problem with Dropbox.

My problem is that for as long as I have tried to figure out, Dropbox made some bold claims about how your files were encrypted and how nobody had access to them, with statements like:

  • All transmission of file data occurs over an encrypted channel (SSL).
  • All files stored on Dropbox servers are encrypted (AES-256)
  • Dropbox employees aren't able to access user files, and when troubleshooting an account they only have access to file metadata (filenames, file sizes, etc., not the file contents)

But anyone that tried to look further came out empty handed. There really are no more details on what procedures Dropbox has in place or how they implement the crypto to prevent unauthorized access to your files. We all had to just take them at their word.

This wishy-washy statement always made me felt uneasy.

But this announcement that they are able to decrypt the files on behalf of the government contradicts their prior public statements. They claim that Dropbox employees aren't able to access user files.

This announcement means that Dropbox never had any mechanism to prevent employees from accessing your files, and it means that Dropbox never had the crypto smarts to ensure the privacy of your files and never had the smarts to only decrypt the files for you. It turns out, they keep their keys on their servers, and anyone with clearance at Dropbox or anyone that manages to hack into their servers would be able to get access to your files.

If companies with a very strict set of security policies and procedures like Google have had problems with employees that abused their privileges, one has to wonder what can happen at a startup like Dropbox where the security perimeter and the policies are likely going to be orders of magnitude laxer.

Dropbox needs to come clear about what privacy do they actually offer in their product. Not only from the government, but from their own employees that could be bribed, blackmailed, making some money on the side or are just plain horny.

Dropbox needs to recruit a neutral third-party to vouch for their security procedures and their security stack that surrounds users' files and privacy. If they are not up to their own marketed statements, they need to clearly specify where their service falls short and what are the potential security breaches that

Unless Dropbox can prove that algorithmically they can protect your keys and only you can get access to your files, they need to revisit their public statements and explicitly state that Dropbox storage should be considered semi-public and not try to sell us snake oil.

Posted on 19 Apr 2011 by Miguel de Icaza
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