Privacy analysis and enhancements for data sharing in *nix systems

Abstract

Linux and its various flavors (together called *nix) are growing in mainstream popularity and many enterprise infrastructures now are based on *nix platforms. An important component of these systems is the ingrained multi-user support that lets users share data with each other.In this paper, we first analyze *nix systems and identify an urgent need for better privacy support in their data sharing mechanisms. In one of our studies it was possible to access over 84 GB of private data at one organization of 836 users, including over 300,000 emails and 579 passwords to financial and other private services websites. The most surprising aspect was the extremely low level of sophistication of the attack. The attack uses no technical vulnerabilities, rather inadequacies of *nix access control combined with user/application's privacy-indifferent behavior.We present two solutions to address this problem: (1) an administrative auditing tool which can alert administrators and users when their private data is at risk, and (2) a new View Based Access Control (VBAC) model which provides stronger and yet convenient privacy support. We also describe a filesystem based implementation and performance analysis of VBAC. A unique property of our implementation is that individual users can choose to switch on/off the VBAC access control model. Our evaluations with three well-known filesystem benchmarks show very little overhead of using VBAC. For example, our implementation resulted in only 3% total overhead with the popular Andrew Benchmark.

Role‐based and time‐bound access and management of EHR data

“…It separated read and write access: read access to the physical storage device is granted to all principals and write access can be granted to everyone. The authors of first analyzed *nix systems and identify an urgent need for better privacy support in their data sharing mechanisms and gave two solutions for privacy enhancement. Later, they proposed a data sharing platform, named SHAROES, for outsourced storage environment.…”

Observations on the UK transformational government strategy relative to citizen data sharing and privacy

“…Further, they posit the argument that this approach is unstable and question its sustainability. Whilst most research undertaken in the field is case related or interpretive, based on secondary data, Singh et al (2008) take a proactive approach by undertaking experiments designed to gain access to private data in a chosen public sector organisation. That they recorded a high level of success without the aid of any technological weaknesses in the organisation provides an insight into the vulnerability of personal data held in the workplace.…”

Sharoes: A Data Sharing Platform for Outsourced Enterprise Storage Environments

“…Most of the related work [7], [8], [11], [12] provides only a restricted access control model with few permission settings. Typically, they only provide read and write permissions at a file level and hierarchical directory permissions are not supported, which studies suggest to be dominant in current local systems [13]. In contrast, the SHAROES system is able to provide rich data sharing semantics by carefully manipulating filesystem metadata and key distribution.…”

“…In other words, a user can not do an "ls" on the directory, but can "cd" into it and access contents by using their exact name. This is a widely used permission in *nix systems and our study at two large organizations showed that greater than 70% of users use exec-only permissions on directories [13]. To support this permission in SHAROES, the directory-table structure requires further manipulation using cryptographic primitives.…”