Relation extraction for inferring access control rules from natural language artifacts

With over forty years of use and refinement, access control, often in the form of access control rules (ACRs), continues to be a significant control mechanism for information security. However, ACRs are typically either buried within existing natural language (NL) artifacts or elicited from subject matter experts. To address the first situation, our research goal is to aid developers who implement ACRs by inferring ACRs from NL artifacts. To aid in rule inference, we propose an approach that extracts relations (i.e., the relationship among two or more items) from NL artifacts such as requirements documents. Unlike existing approaches, our approach combines techniques from information extraction and machine learning. We develop an iterative algorithm to discover patterns that represent ACRs in sentences. We seed this algorithm with frequently occurring nouns matching a subject--action--resource pattern throughout a document. The algorithm then searches for additional combinations of those nouns to discover additional patterns. We evaluate our approach on documents from three systems in three domains: conference management, education, and healthcare. Our evaluation results show that ACRs exist in 47% of the sentences, and our approach effectively identifies those ACR sentences with a precision of 81% and recall of 65%; our approach extracts ACRs from those identified ACR sentences with an average precision of 76% and an average recall of 49%.