Biblio

With the integration of computing, communication, and physical processes, the modern power grid is becoming a large and complex cyber physical power system (CPPS). This trend is intended to modernize and improve the efficiency of the power grid, yet it makes the CPPS vulnerable to potential cascading failures caused by cyber-attacks, e.g., the attacks that are originated by the cyber network of CPPS. To prevent these risks, it is essential to analyze how cyber-attacks can be conducted against the CPPS and how they can affect the power systems. In light of that General Packet Radio Service (GPRS) has been widely used in CPPS, this paper provides a case study by examining possible cyber-attacks against the cyber-physical power systems with GPRS-based SCADA system. We analyze the vulnerabilities of GPRS-based SCADA systems and focus on DoS attacks and message spoofing attacks. Furthermore, we show the consequence of these attacks against power systems by a simulation using the IEEE 9-node system, and the results show the validity of cascading failures propagated through the systems under our proposed attacks.

Software Defined Networking (SDN) is a paradigm shift that changes the working principles of IP networks by separating the control logic from routers and switches, and logically centralizing it within a controller. In this architecture the control plane (controller) communicates with the data plane (switches) through a control channel using a standards-compliant protocol, that is, OpenFlow. While having a centralized controller creates an opportunity to monitor and program the entire network, as a side effect, it causes the control plane to become a single point of failure. Denial of service (DoS) attacks or even heavy control traffic conditions can easily become real threats to the proper functioning of the controller, which indirectly detriments the entire network. In this paper, we propose a solution to reduce the control traffic generated primarily during table-miss events. We utilize the buffer\_id feature of the OpenFlow protocol, which has been designed to identify individually buffered packets within a switch, reusing it to identify flows buffered as a series of packets during table-miss, which happens when there is no related rule in the switch flow tables that matches the received packet. Thus, we allow the OpenFlow switch to send only the first packet of a flow to the controller for a table-miss while buffering the rest of the packets in the switch memory until the controller responds or time out occurs. The test results show that OpenFlow traffic is significantly reduced when the proposed method is used.

Algorithmic complexity vulnerabilities occur when the worst-case time/space complexity of an application is significantly higher than the respective average case for particular user-controlled inputs. When such conditions are met, an attacker can launch Denial-of-Service attacks against a vulnerable application by providing inputs that trigger the worst-case behavior. Such attacks have been known to have serious effects on production systems, take down entire websites, or lead to bypasses of Web Application Firewalls. Unfortunately, existing detection mechanisms for algorithmic complexity vulnerabilities are domain-specific and often require significant manual effort. In this paper, we design, implement, and evaluate SlowFuzz, a domain-independent framework for automatically finding algorithmic complexity vulnerabilities. SlowFuzz automatically finds inputs that trigger worst-case algorithmic behavior in the tested binary. SlowFuzz uses resource-usage-guided evolutionary search techniques to automatically find inputs that maximize computational resource utilization for a given application. We demonstrate that SlowFuzz successfully generates inputs that match the theoretical worst-case performance for several well-known algorithms. SlowFuzz was also able to generate a large number of inputs that trigger different algorithmic complexity vulnerabilities in real-world applications, including various zip parsers used in antivirus software, regular expression libraries used in Web Application Firewalls, as well as hash table implementations used in Web applications. In particular, SlowFuzz generated inputs that achieve 300-times slowdown in the decompression routine of the bzip utility, discovered regular expressions that exhibit matching times exponential in the input size, and also managed to automatically produce inputs that trigger a high number of collisions in PHP's default hashtable implementation.

This paper studies the stability of event-triggered control systems subject to Denial-of-Service attacks. An improved method is provided to increase frequency and duration of the DoS attacks where closed-loop stability is not destroyed. A two-mode switching control method is adopted to maintain stability of event-triggered control systems in the presence of attacks. Moreover, this paper reveals the relationship between robustness of systems against DoS attacks and lower bound of the inter-event times, namely, enlarging the inter-execution time contributes to enhancing the robustness of the systems against DoS attacks. Finally, some simulations are presented to illustrate the efficiency and feasibility of the obtained results.

Software-defined networking (SDN) separates the control plane from underlying devices, and allows it to control the data plane from a global view. While SDN brings conveniences to management, it also introduces new security threats. Knowing reactive rules, attackers can launch denial-of-service (DoS) attacks by sending numerous rule-matched packets which trigger packet-in packets to overburden the controller. In this work, we present a novel method ``INferring SDN by Probing and Rule Extraction'' (INSPIRE) to discover the flow rules in SDN from probing packets. We evaluate the delay time from probing packets, classify them into defined classes, and infer the rules. This method involves three relevant steps: probing, clustering and rule inference. First, forged packets with various header fields are sent to measure processing and propagation time in the path. Second, it classifies the packets into multiple classes by using k-means clustering based on packet delay time. Finally, the apriori algorithm will find common header fields in the classes to infer the rules. We show how INSPIRE is able to infer flow rules via simulation, and the accuracy of inference can be up to 98.41% with very low false-positive rates.

Software Defined Networks (SDNs) have gained prominence recently due to their flexible management and superior configuration functionality of the underlying network. SDNs, with OpenFlow as their primary implementation, allow for the use of a centralised controller to drive the decision making for all the supported devices in the network and manage traffic through routing table changes for incoming flows. In conventional networks, machine learning has been shown to detect malicious intrusion, and classify attacks such as DoS, user to root, and probe attacks. In this work, we extend the use of machine learning to improve traffic tolerance for SDNs. To achieve this, we extend the functionality of the controller to include a resilience framework, ReSDN, that incorporates machine learning to be able to distinguish DoS attacks, focussing on a neptune attack for our experiments. Our model is trained using the MIT KDD 1999 dataset. The system is developed as a module on top of the POX controller platform and evaluated using the Mininet simulator.

Security in cloud environments is always considered an issue, due to the lack of control over leased resources. In this paper, we present a solution that offers security-as-a-service by relying on Security Service Level Agreements (Security SLAs) as a means to represent the security features to be granted. In particular, we focus on a security mechanism that is automatically configured and activated in an as-a-service fashion in order to protect cloud resources against DoS attacks. The activities reported in this paper are part of a wider work carried out in the FP7-ICT programme project SPECS, which aims at building a framework offering Security-as-a-Service using an SLA-based approach. The proposed approach founds on the adoption of SPECS Services to negotiate, to enforce and to monitor suitable security metrics, chosen by cloud customers, negotiated with the provider and included in a signed Security SLA.

Cultivation of Smart Grid refurbish with brisk and ingenious. The delinquent breed and sow mutilate in massive. This state of affair coerces security as a sapling which incessantly is to be irrigated with Research and Analysis. The Cyber Security is endowed with resiliency to the SYN flooding induced Denial of Service attack in this work. The proposed secure web server algorithm embedded in the LPC1768 processor ensures the smart resources to be precluded from the attack.

The issue of security has become ever more prevalent in the analysis and design of cyber-physical systems. In this paper, we analyze a consensus network in the presence of Denial-of-Service (DoS) attacks, namely attacks that prevent communication among the network agents. By introducing a notion of Persistency-of-Communication (PoC), we provide a characterization of DoS frequency and duration such that consensus is not destroyed. An example is given to substantiate the analysis.

The future of ambient assisted living (AAL) especially eHealthcare almost depends on the smart objects that are part of the Internet of things (IoT). In our AAL scenario, these objects collect and transfer real-time information about the patients to the hospital server with the help of Wireless Mesh Network (WMN). Due to the multi-hop nature of mesh networks, it is possible for an adversary to reroute the network traffic via many denial of service (DoS) attacks, and hence affect the correct functionality of the mesh routing protocol. In this paper, based on a comparative study, we choose the most suitable secure mesh routing protocol for IoT-based AAL applications. Then, we analyze the resilience of this protocol against DoS attacks. Focusing on the hello flooding attack, the protocol is simulated and analyzed in terms of data packet delivery ratio, delay, and throughput. Simulation results show that the chosen protocol is totally resilient against DoS attack and can be one of the best candidates for secure routing in IoT-based AAL applications.

Denial-of-Service (DoS) attacks pose a threat to any service provider on the internet. While traditional DoS flooding attacks require the attacker to control at least as much resources as the service provider in order to be effective, so-called low-rate DoS attacks can exploit weaknesses in careless design to effectively deny a service using minimal amounts of network traffic. This paper investigates one such weakness found within version 2.2 of the popular Apache HTTP Server software. The weakness concerns how the server handles the persistent connection feature in HTTP 1.1. An attack simulator exploiting this weakness has been developed and shown to be effective. The attack was then studied with spectral analysis for the purpose of examining how well the attack could be detected. Similar to other papers on spectral analysis of low-rate DoS attacks, the results show that disproportionate amounts of energy in the lower frequencies can be detected when the attack is present. However, by randomizing the attack pattern, an attacker can efficiently reduce this disproportion to a degree where it might be impossible to correctly identify an attack in a real world scenario.

Denial-of-Service (DoS) and probe attacks are growing more modern and sophisticated in order to evade detection by Intrusion Detection Systems (IDSs) and to increase the potent threat to the availability of network services. Detecting these attacks is quite tough for network operators using misuse-based IDSs because they need to see through attackers and upgrade their IDSs by adding new accurate attack signatures. In this paper, we proposed a novel signal and image processing-based method for detecting network probe and DoS attacks in which prior knowledge of attacks is not required. The method uses a time-frequency representation technique called S-transform, which is an extension of Wavelet Transform, to reveal abnormal frequency components caused by attacks in a traffic signal (e.g., a time-series of the number of packets). Firstly, S-Transform converts the traffic signal to a two-dimensional image which describes time-frequency behavior of the traffic signal. The frequencies that behave abnormally are discovered as abnormal regions in the image. Secondly, Otsu's method is used to detect the abnormal regions and identify time that attacks occur. We evaluated the effectiveness of the proposed method with several network probe and DoS attacks such as port scans, packet flooding attacks, and a low-intensity DoS attack. The results clearly indicated that the method is effective for detecting the probe and DoS attack streams which were generated to real-world Internet.

The Internet is vulnerable to bandwidth distributed denial-of-service (BW-DDoS) attacks, wherein many hosts send a huge number of packets to cause congestion and disrupt legitimate traffic. So far, BW-DDoS attacks have employed relatively crude, inefficient, brute force mechanisms; future attacks might be significantly more effective and harmful. To meet the increasing threats, we must deploy more advanced defenses.

The security of Smart Grid, being one of the very important aspects of the Smart Grid system, is studied in this paper. We first discuss different pitfalls in the security of the Smart Grid system considering the communication infrastructure among the sensors, actuators, and control systems. Following that, we derive a mathematical model of the system and propose a robust security framework for power grid. To effectively estimate the variables of a wide range of state processes in the model, we adopt Kalman Filter in the framework. The Kalman Filter estimates and system readings are then fed into the χ2-square detectors and the proposed Euclidean detectors, which can detect various attacks and faults in the power system including False Data Injection Attacks. The χ2-detector is a proven-effective exploratory method used with Kalman Filter for the measurement of the relationship between dependent variables and a series of predictor variables. The χ2-detector can detect system faults/attacks such as replay and DoS attacks. However, the study shows that the χ2-detector detectors are unable to detect statistically derived False Data Injection Attacks while the Euclidean distance metrics can identify such sophisticated injection attacks.