An efficient approach to online bot detection based on a reinforcement learning technique

In recent years, Botnets have been adopted as a popular method used to carry and spread many malicious codes on the Internet. These codes pave the way to conducting many fraudulent activities, including spam mail, distributed denial of service attacks (DDoS) and click fraud. While many Botnets are set up using a centralized communication architecture such as Internet Relay Chat (IRC) and Hypertext Transfer Protocol (HTTP), peer-to-peer (P2P) Botnets can adopt a decentralized architecture using an overlay network for exchanging command and control (C&C) messages, which is a more resilient and robust communication channel infrastructure. Without a centralized point for C&C servers, P2P Botnets are more flexible to defeat countermeasures and detection procedures than traditional centralized Botnets. Several Botnet detection techniques have been proposed, but Botnet detection is still a very challenging task for the Internet security community because Botnets execute attacks stealthily in the dramatically growing volumes of network traffic. However, current Botnet detection schemes face significant problem of efficiency and adaptability. The present study combined a traffic reduction approach with reinforcement learning (RL) method in order to create an online Bot detection system. The proposed framework adopts the idea of RL to improve the system dynamically over time. In addition, the traffic reduction method is used to set up a lightweight and fast online detection method. Moreover, a host feature based on traffic at the connection-level was designed, which can identify Bot host behaviour. Therefore, the proposed technique can potentially be applied to any encrypted network traffic since it depends only on the information obtained from packets header. Therefore, it does not require Deep Packet Inspection (DPI) and cannot be confused with payload encryption techniques. The network traffic reduction technique reduces packets input to the detection system, but the proposed solution achieves good a detection rate of 98.3% as well as a low false positive rate (FPR) of 0.012% in the online evaluation. Comparison with other techniques on the same dataset shows that our strategy outperforms existing methods. The proposed solution was evaluated and tested using real network traffic datasets to increase the validity of the solution

Command & Control: Understanding, Denying and Detecting - A review of malware C2 techniques, detection and defences

In this survey, we first briefly review the current state of cyber attacks, highlighting significant recent changes in how and why such attacks are performed. We then investigate the mechanics of malware command and control (C2) establishment: we provide a comprehensive review of the techniques used by attackers to set up such a channel and to hide its presence from the attacked parties and the security tools they use. We then switch to the defensive side of the problem, and review approaches that have been proposed for the detection and disruption of C2 channels. We also map such techniques to widely-adopted security controls, emphasizing gaps or limitations (and success stories) in current best practices.Comment: Work commissioned by CPNI, available at c2report.org. 38 pages. Listing abstract compressed from version appearing in repor

Storytelling Security: User-Intention Based Traffic Sanitization

Malicious software (malware) with decentralized communication infrastructure, such as peer-to-peer botnets, is difficult to detect. In this paper, we describe a traffic-sanitization method for identifying malware-triggered outbound connections from a personal computer. Our solution correlates user activities with the content of outbound traffic. Our key observation is that user-initiated outbound traffic typically has corresponding human inputs, i.e., keystroke or mouse clicks. Our analysis on the causal relations between user inputs and packet payload enables the efficient enforcement of the inter-packet dependency at the application level. We formalize our approach within the framework of protocol-state machine. We define new application-level traffic-sanitization policies that enforce the inter-packet dependencies. The dependency is derived from the transitions among protocol states that involve both user actions and network events. We refer to our methodology as storytelling security. We demonstrate a concrete realization of our methodology in the context of peer-to-peer file-sharing application, describe its use in blocking traffic of P2P bots on a host. We implement and evaluate our prototype in Windows operating system in both online and offline deployment settings. Our experimental evaluation along with case studies of real-world P2P applications demonstrates the feasibility of verifying the inter-packet dependencies. Our deep packet inspection incurs overhead on the outbound network flow. Our solution can also be used as an offline collect-and-analyze tool

A Survey of Botnet Detection Techniques by Command and Control Infrastructure

Botnets have evolved to become one of the most serious threats to the Internet and there is substantial research on both botnets and botnet detection techniques. This survey reviewed the history of botnets and botnet detection techniques. The survey showed traditional botnet detection techniques rely on passive techniques, primarily honeypots, and that honeypots are not effective at detecting peer-to-peer and other decentralized botnets. Furthermore, the detection techniques aimed at decentralized and peer-to-peer botnets focus on detecting communications between the infected bots. Recent research has shown hierarchical clustering of flow data and machine learning are effective techniques for detecting botnet peer-to-peer traffic

A Covert Data Transport Protocol

Both enterprise and national firewalls filter network connections. For data forensics and botnet removal applications, it is important to establish the information source. In this paper, we describe a data transport layer which allows a client to transfer encrypted data that provides no discernible information regarding the data source. We use a domain generation algorithm (DGA) to encode AES encrypted data into domain names that current tools are unable to reliably differentiate from valid domain names. The domain names are registered using (free) dynamic DNS services. The data transmission format is not vulnerable to Deep Packet Inspection (DPI).Comment: 8 pages, 10 figures, conferenc

Securing Enterprise Networks with Statistical Node Behavior Profiling

The substantial proliferation of the Internet has made it the most critical infrastructure in today\u27s world. However, it is still vulnerable to various kinds of attacks/malwares and poses a number of great security challenges. Furthermore, we have also witnessed in the past decade that there is always a fast self-evolution of attacks/malwares (e.g. from worms to botnets) against every success in network security. Network security thereby remains a hot topic in both research and industry and requires both continuous and great attention. In this research, we consider two fundamental areas in network security, malware detection and background traffic modeling, from a new view point of node behavior profiling under enterprise network environments. Our main objectives are to extend and enhance the current research in these two areas. In particular, central to our research is the node behavior profiling approach that groups the behaviors of different nodes by jointly considering time and spatial correlations. We also present an extensive study on botnets, which are believed to be the largest threat to the Internet. To better understand the botnet, we propose a botnet framework and predict a new P2P botnet that is much stronger and stealthier than the current ones. We then propose anomaly malware detection approaches based directly on the insights (statistical characteristics) from the node behavior study and apply them on P2P botnet detection. Further, by considering the worst case attack model where the botmaster knows all the parameter values used in detection, we propose a fast and optimized anomaly detection approach by formulating the detection problem as an optimization problem. In addition, we propose a novel traffic modeling structure using behavior profiles for NIDS evaluations. It is efficient and takes into account the node heterogeneity in traffic modeling. It is also compatible with most current modeling schemes and helpful in generating better realistic background traffic. Last but not least, we evaluate the proposed approaches using real user trace from enterprise networks and achieve encouraging results. Our contributions in this research include: 1) a new node behavior profiling approach to study the normal node behavior; 2) a framework for botnets; 3) a new P2P botnet and performance comparisons with other P2P botnets; 4) two anomaly detection approaches based on node behavior profiles; 4) a fast and optimized anomaly detection approach under the worst case attack model; 5) a new traffic modeling structure and 6) simulations and evaluations of the above approaches under real user data from enterprise networks. To the best of our knowledge, we are the first to propose the botnet framework, consider the worst case attack model and propose corresponding fast and optimized solution in botnet related research. We are also the first to propose efficient solutions in traffic modeling without the assumption of node homogeneity