With the webs explosive growth in power and popularity has come a concomitant increase in both the number and impact of cyber criminals. For years businesses have striven to keep malware, spam and unwanted intruders at bay with varying degrees of success. Cyber criminals and spies in turn created more advanced means to breach the security measures. APTs are a new and more sophisticated version of known multistep attack scenarios and they are targeted specifically to achieve a specific goal, most often espionage. The financial loss caused by APT attacks can be very big. Moreover, these APTs form a problem for the current detection methods because these methods depend on known signatures of attacks and APTs make heavy use of unknown security holes for attacks. In this paper we present an overview of the current researches about APT attack detection. In addition, we provide a classification of these researches into three groups which are previous research findings on APT attack, Analyzing already identified of APTs and detect possible APT attack.