Access Control Policy Extraction from Unconstrained Natural Language Text

Abstract

While access control mechanisms have existed in computer systems since the 1960s, modern system developers often fail to ensure appropriate mechanisms are implemented within particular systems. Such failures allow for individuals, both benign and malicious, to view and manipulate information that they should not otherwise be able to access. The goal of our research is to help developers improve security by extracting the access control policies implicitly and explicitly defined in natural language project artifacts. Developers can then verify and implement the extracted access control policies within a system. We propose a machine-learning based process to parse existing, unaltered natural language documents, such as requirement or technical specifications to extract the relevant subjects, actions, and resources for an access control policy. To evaluate our approach, we analyzed a public requirements specification. We had a precision of 0.87 with a recall of 0.91 in classifying sentences as access control or not. Through a bootstrapping process utilizing dependency graphs, we correctly identified the subjects, actions, and objects elements of the access control policies with a precision of 0.46 and a recall of 0.54.