12-05-2012, 05:24 PM
Layered Approach Using Conditional Random Fields for Intrusion Detection
Layered Approach Using Conditional Random Fields for Intrusion Detection.doc (Size: 1.06 MB / Downloads: 38)
Abstract:
Intrusion detection faces a number of challenges; an intrusion detection system must reliably detect malicious activities in a network and must perform efficiently to cope with the large amount of network traffic. In this project, we address these two issues of Accuracy and Efficiency using Conditional Random Fields and Layered Approach. We demonstrate that high attack detection accuracy can be achieved by using Conditional Random Fields and high efficiency by implementing the Layered Approach. Finally, we show that our system is robust and is able to handle noisy data without compromising performance.
Existing System:-
The field of intrusion detection and network security has been around since late 1980s. Since then, a number of methods and frameworks have been proposed and many systems have been built to detect intrusions. Various techniques such as association rules, clustering, naive Bayes classifier, support vector machines, genetic algorithms, artificial neural networks, and others have been applied to detect intrusions. In this section, we briefly discuss these techniques and frameworks.
Experimental results on the benchmark KDD ’99 intrusion data set show that our proposed system based on Layered Conditional Random Fields outperforms other well-known methods such as the decision trees and the naive Bayes.
The improvement in attack detection accuracy is very high, particularly, for the U2R attacks (34.8 percent improvement) and the R2L attacks (34.5 percent improvement). Statistical Tests also demonstrate higher confidence in detection accuracy for our method.
Proposed System:-
Other approaches for detecting intrusion include the use of autonomous and probabilistic agents for intrusion detection. These methods are generally aimed at developing a distributed intrusion detection system. To overcome the weakness of a single intrusion detection system, a number of frameworks have been proposed, which describe the collaborative use of network-based and hostbased systems . Systems that employ both signature based and behavior-based techniques are discussed in the authors describe a data mining framework for building adaptive intrusion detection models.
The data analyzed by the intrusion detection system for classification often has a number of features that are highly correlated and complex relationships exist between them. when classifying network connections as either normal or as attack, a system may consider features such as “logged in” and “number of file creations.” When these features are analyzed individually, they do not provide any information that can aid in detecting attacks. However, when these features are analyzed together, they can provide meaningful information, which can be helpful for the classification task. And connection level feature such as the “service invoked” at the
Two Approach
INTEGRATING LAYERED APPROACH WITH CONDITIONAL RANDOM FIELD
We now describe the Layer-based Intrusion Detection System (LIDS) in detail. The LIDS draws its motivation from what we call as the Airport Security model, where a number of security checks are performed one after the other in a sequence. Similar to this model, the LIDS represents a sequential Layered Approach and is based on ensuring availability, confidentiality, and integrity of data and (or) services over a network.
The goal of using a layered model is to reduce computation and the overall time required to detect anomalous events. The time required to detect an intrusive event is significant and can be reduced by eliminating the communication overhead among different layers. This can be achieved by making the layers autonomous and self-sufficient to block an attack without the need of a central decision-maker. Every layer in
the LIDS framework is trained separately and then deployed sequentially. We define four layers that correspond to the four attack groups mentioned in the data set.
Each layer is then separately trained with a small set of relevant features. Feature selection is significant for Layered Approach and discussed in the next section.
In order to make the layers independent, some features may be present in more than one layer. The layers essentially act as filters that block any anomalous connection, thereby eliminating the need of further processing at subsequent layers enabling quick response to intrusion. The effect of such a sequence of layers is that the anomalous events are identified and blocked as soon as they are detected.