  In recent years, traditional cybersecurity safeguards have proven ineffective
against insider threats. Famous cases of sensitive information leaks caused by
insiders, including the WikiLeaks release of diplomatic cables and the Edward
Snowden incident, have greatly harmed the U.S. government's relationship with
other governments and with its own citizens. Data Leak Prevention (DLP) is a
solution for detecting and preventing information leaks from within an
organization's network. However, state-of-art DLP detection models are only
able to detect very limited types of sensitive information, and research in the
field has been hindered due to the lack of available sensitive texts. Many
researchers have focused on document-based detection with artificially labeled
"confidential documents" for which security labels are assigned to the entire
document, when in reality only a portion of the document is sensitive. This
type of whole-document based security labeling increases the chances of
preventing authorized users from accessing non-sensitive information within
sensitive documents. In this paper, we introduce Automated Classification
Enabled by Security Similarity (ACESS), a new and innovative detection model
that penetrates the complexity of big text security classification/detection.
To analyze the ACESS system, we constructed a novel dataset, containing
formerly classified paragraphs from diplomatic cables made public by the
WikiLeaks organization. To our knowledge this paper is the first to analyze a
dataset that contains actual formerly sensitive information annotated at
paragraph granularity.
