A Protocol-Independent Botnet Detection Method Using Flow Similarity

The detection of botnets has always been a hot spot in the field of network security. However, there are still many challenges in botnet detection. Most of the current botnet detection approaches, such as machine learning and blacklists, cannot discover evolving botnet variants. These methods are usually only valid for specific botnet protocols which are not general. Even they may be difficult to deal with encrypted botnet traffic. In this paper, we design a protocol-independent botnet detection method for these challenges. Our detection method takes advantage of the group characteristic of the botnet, which is the inherent characteristics of the botnet. We use the sequence of packet length as the characteristic of a flow. Then, we calculate the similarity between these sequences to detect botnets. Our method has an excellent generality, which is not affected by encrypted traffic and the protocols of the botnet. Experiments on a challenging dataset ISCX show that the proposed method can effectively detect botnets with a high average detection rate and low false alarm, which significantly outperforms the state-of-the-art methods. Therefore, the proposed detection method is robust and has a wide range of adaptability in detecting botnets.