Sensitivity & Specificity

Borrowing terms from medical testing

Sensitivity and specificity are statistical measures originally used in the field of medical testing to evaluate the performance of diagnostic tests, but these concepts can also be applied to the realm of data loss prevention (DLP) in cybersecurity. In the context of DLP, sensitivity (also known as the true positive rate) and specificity (also known as the true negative rate) are used to assess the effectiveness of DLP systems in identifying and preventing unauthorized data transfers without impeding legitimate data use.

Sensitivity

Sensitivity in DLP refers to the system’s ability to correctly identify and block actual instances of data loss or unauthorized data transfers. A high sensitivity means the DLP system is effective at catching breaches of data security, minimizing the risk of sensitive information being exposed or stolen. However, if the system is too sensitive, it could produce high number of false positives, potentially disrupting business operations or burying the true positives in a pile of false ones which security operations then needs to sort through.

Specificity

Specificity in DLP, on the other hand, measures the system’s ability to correctly allow legitimate data transfers while blocking only the unauthorized ones. A high specificity means the system accurately distinguishes between permissible and impermissible actions, allowing normal business activities to proceed without interruption. In other words, a highly specific DLP system will have few false positives.

Striking a balance

Balancing sensitivity and specificity in a DLP system is crucial. An ideal DLP system would have both high sensitivity (to catch as many real threats as possible) and high specificity (to avoid impeding business processes with false alarms). Achieving this balance ensures that sensitive data is protected from unauthorized access and transfer, while legitimate data use and business operations are not unnecessarily hindered.

Today’s lab will take you through a few common strategies for implementing DLP which will vary in balance between sensitivity and specificity and help you understand which strategies would best fit your organizations needs.