  Shared folders are still a common practice for granting third parties access
to data files, regardless of the advances in data sharing technologies.
Services like Google Drive, Dropbox, Box, and others, provide infrastructures
and interfaces to manage file sharing. The human factor is the weakest link and
data leaks caused by human error are regrettable common news. This takes place
as both mishandled data, for example stored to the wrong directory, or via
misconfigured or failing applications dumping data incorrectly. We present Data
Leakage Prevention FileSystem (DLPFS), a first attempt to systematically
protect against data leakage caused by misconfigured application or human
error. This filesystem interface provides a privacy protection layer on top of
the POSIX filesystem interface, allowing for seamless integration with existing
infrastructures and applications, simply augmenting existing security controls.
At the same time, DLPFS allows data administrators to protect files shared
within an organisation by preventing unauthorised parties to access potentially
sensitive content. DLPFS achieves this by transparently integrating with
existing access control mechanisms. We empirically evaluate the impact of DLPFS
on system's performances to demonstrate the feasibility of the proposed
solution.
