Abstract: An apparatus for detecting a network attack includes a traffic image generator for generating a traffic image using traffic information and additional IP information extracted from the traffic information; a network attack detector for comparing similarities between the traffic image and a previously generated traffic image based on a predetermined similarity threshold to detect the presence of the network attack; and a network attack analyzer for analyzing the traffic image at a time when the network attack is detected to detect network attack information and pattern information of the network attack. A representation unit for visualizing the network attack information and the pattern information of the network attack.