© 2017 ACM. Everyday, security- experts face a grim ing number of security events that affecting people well-being, their information systems and sometimes the critical infrastructure. The sooner they can detect and understand these threats, the more they can mitigate and forensically investigate them Therefore, they need to have a situation awareness of the existing security events and their possible effects. However, given the large number of events, it can be difficult for security analysts and researchers to handle this flow of information in an adequate manner and answer the following questions in near- real time: what are the current security events? How long do they last? In this paper, we will try to answer these issues by leveraging social networks that contain a massive amount of valuable information on many topics. I lowever. because of the very- high volume, extracting meaningful information can be challenging. For this reason, we propose SONAR: An automatic, self-learned framework that can detect geolocate and categorize cyber security events in near-real time over the Twitter stream. SONAR is based on a taxonomy- of cyber security events and a set of seed keywords describing type of events that we want to follow in order to start detecting events. Using these seed keywords, it automatically discovers new relevant keywords such as malware names to enhance the range of detection while staying in the same domain. Using a custom taxonomy describing all type of cyber threats, we demonstrate the capabilities of SONAR on a dataset of approximately 47.8 million tweets related to cyber security in the last 9 months. SONAR could efficiently and effectively detect, categorize and monitor cyber security related events before getting on the security news, and it could automatically discover new security terminologies with their event. Additionally. SONAR is highly scalable and customizable by design; therefore we could adapt SONAR framework for virtually any type of events that experts are interested in.