Classification of Network Intrusion Attacks Using Machine Learning and Deep Learning^
P. Roshni Mol 1*, Dr. C. Immaculate Mary2
1 Ph.D. Research Scholar, Department of Computer Science, Sri Sarada College for Women (Autonomous), Salem, Tamilnadu, India.
2H.O.D & Associate Professor, Department of Computer Science, Sri Sarada College for Women (Autonomous), Salem, Tamilnadu, India.
1[email protected], 2[email protected]
Modern era is loaded with data. Increase in usage of smart phones results in enormous amount of data generation. Highly sophisticated smart cities enabled with Internet of Things (IoT) devices produces large data. Sensitive data such as personal information, health information, financial information may be vulnerable and it’s integrity could be lost. Highly voluminous data travelling to and fro through the network may encounter traffic. This network traffic can be either normal traffic or it may be intrusion created by the hacker to hack by introducing abnormal traffic over the network. Traditional Intrusion detection systems and firewalls may detect the attacks based on the signature pattern. This is not sufficient to detect the advance persistent threats or to detect unknown attacks. To identify and to classify various types of unknown attacks, it is essential to apply intelligent techniques. This paper aims to classify attacks like DoS (Denial of Service), Probe, R2L (Remote to Local), U2R (User to Root) which causes intrusion in the network. To identify and to analyze root cause of intrusion, a benchmark dataset named NSL-KDD (Network Security Laboratory- Knowledge Discovery and Data) is used. Detailed analysis of the NSL- KDD dataset is accomplished by using machine learning and deep learning. Four models are opted to perform comparative analysis. In the first model, Principal Component Analysis (PCA) is applied to minimize the dimension of data and machine Learning algorithms like logistic Regression, Random forest Classifier, Decision Tree Classifier are utilized to build the model. In the second model, algorithms like logistic Regression, Random forest Classifier, Decision Tree Classifier, Adaboost, and XGBoost are used.
In the third model, multi-label classifier chains algorithm is applied to deploy the model. In the fourth model, deep neural network is used to accomplish deep learning model. The motive of this research is to find the best classifier that classifies data with high accuracy and to develop a model which serves the best for intrusion detection system. Comparative analysis of classifier algorithms is done and it is evident that, in the first model, Random forest algorithm produces 98.7% accuracy, in the second model, Adaboost algorithm produces 99.8% accuracy, in the third model, Multi label classifier chain based on random forest produces 99.6% accuracy and in the fourth model, deep neural network produces 99.2% accuracy.
Among the four models, it is found that, Adaboost is the best algorithm which classifies and produces best results.
Keywords— NSL-KDD, Machine Learning, Deep Learning, Multi label classification, Intrusion detection
In this digital era, lots of data are transferred to and fro from source to destination. Due to COVID-19 (Coronavirus) pandemic situation, educational field as well as other fields are drawn to adapt online mode for learning and working. An article from Hindustan Times  reports that, Department of Telecommunications had collected data between 22 March 2020 and 28 March 2020 and states that Indians consumed internet on an average of 307 Petabytes of data. Most of the people started to watch videos and it has raised the traffic by 30%. It is essential to check the quality of the traffic. Technology evolves day by day to fulfil and to serve human needs but on the other end, dark side of the technology also evolves itself rapidly. Cyber security plays a major role for an organization or an enterprise to ensure its security within and outside the network. Intruders may intrude the network to collect sensitive information, to flood the network with malicious traffic. To handle these intruders, it is a pre requisite to set up an Intrusion
Detection System (IDS). James P. Anderson, of United States Air force  submitted a report on
“Computer Security Threat Monitoring and Surveillance” in 1980. Based on this report, first IDS was developed. IDS collect traffic data and segregates to normal or malicious traffic. Data such as network traffic, system log, application log, security log can be collected for analysis. Proprietary or open source tools can be opted to gather streaming data. Proprietary tools like Fortinet, Sourcefire ,TippingPoint, etc.,are available. Bro-IDS, Samhain Labs, OpenDLP, OSSEC, Snort, Suricata,etc., are some of the freely available tools. Simulation tools can be used to mimic the network attacks and it is processed for analysis.
Hackers or intruders may generate malicious traffic that leads to Denial of Service attack, probing attack etc. For a secured organization only Firewall and SEIM (Security Events and Information Management) is not sufficient. An IDS is required to handle intrusion in the network. After data acquisition, data analysis can be performed that is based on Anomaly-based IDS or Misuse-based IDS. Malicious traffic may result in denial of service attack, probing attack, privilege escalation attack, reconnaissance attack etc. IDS can be categorized into Network IDS, Host IDS, Network Node IDS, Protocol IDS, Wireless IDS, Network Behavior Analysis (NBA).There are various approaches for intrusion detection system. It can be statistics, rule, pattern, state and heuristic based detection. After the detection of intrusion or attack, alert will be generated. Existing Intrusion Detection System works well for already known attacks based on the signature and pattern of the particular attack. It is essential to develop IDS and IPS to handle advance persistent threats. This can be achieved through various machine and deep learning algorithms.
2. MACHINE LEARNING FOR INTRUSION DETECTION
Machine learning algorithms are categorized into supervised and unsupervised algorithms. If the label is available and if the target feature is known, then supervised algorithm can be applied. If the label is unknown and if the target feature is not available, unsupervised algorithms can be applied. Support Vector Machine (SVM), Artificial Neural Network (ANN), Navie Bayes, Logistic Regression, Decision Tree, K- Nearest Neighbors (KNN), Random Forest are some of the supervised algorithms. Supervised algorithms perform classification. Unsupervised algorithms perform clustering. K-means clustering, Hierarchical clustering, K-NN (k nearest neighbors) are some of the unsupervised algorithms.
2.1. DATA ACQUISITION
Data can be collected from sources like Host and Network side. Host-based IDS detects the unusual traffic flow in the particular host system. Network-based IDS detects the malicious traffic among the systems which are in network. DARPA1998, KDD99, NSL-KDD, UNSW-NB15, CTU-13 etc., are some of the benchmark intrusion datasets which are available online . Benchmark datasets for intrusion are inadequate. It is essential to create new datasets for research. In this paper to recognize and to categorize intrusion attacks like DoS, Probe, U2R and R2L, NSL-KDD  dataset is utilized.
2.2. EXPLORATORY DATA ANALYSIS
Once data is collected, it is essential to perform exploratory data analysis to find the correlation between the attributes or features. Outlier can be identified using visualization, so that it can be eliminated to get accurate results. Overall summary of the data can be acquired using the statistical functions like count, Count, Mean, Standard Deviation, Minimum Value, Maximum Value,25th , 50th and 75th Percentile.
2.3. DATA PRE-PROCESSING
Data pre-processing is a necessary process in machine learning life cycle. Inconsistencies and duplicates in data are removed in this step. Feature scaling, feature transformation and feature selection is performed while pre-processing the data. Yuyang Zhou  proposed Bat algorithm based on correlation, as feature selection technique by applying C4.5, random forest classifiers. Senthilnayaki  used Information gain as feature selection for KDD cup 99 dataset. Shailendra Sahu used PSO(Particle Swarm Optimization) with Gradient decision tree for feature selection. Selvakumar B et al.  used PCA for feature selection to process KDD cup 99.
In this paper feature scaling is done using Standard Scaler, Label Encoder and Label Binarizer.
Standard scalar makes use of z-score normalization so that all values are converted to a specific range.
Label Encoder is used to handle categorical attributes by assigning a value to the labels. One hot encoding is done for categorical features. Label Binarizer replaces categorical values with array of numbers. PCA is
used to minimize the dimension of the dataset.
2.4. MODEL GENERATION AND VALIDATION
Y.Bouzida  used SVM, multilayer perception classifier on NSL-KDD, ISCX and Kyoto 2006 datasets. Mohamoud M  used combined binary PSO, Standard PSO and SVM to process NSL-KDD dataset. S. Balakrishnan  applied SVM with Rule based classification on NSL-KDD and achieved better accuracy. Ripon Patgiri  used Random forest and SVM along with Recursive feature elimination technique.
In this paper, supervised algorithms like decision tree, adaboost, xgboost, logistic regression, random forest are used to create machine learning model which classifies different attacks into different classes. A classifier chain is applied to deal with multi label classification.
3. DEEP LEARNING FOR INTRUSION DETECTION
Deep learning can be used to detect anomalous traffic. Deep learning algorithm learns by itself and finds the anomalous traffic from normal traffic. Basic units of neural network are neurons, neuron weights, activation function, network of neurons, input, hidden and output layers. In this paper basic neural network is used for analysis. Keras is used to create deep neural network, relu and softmax are passed as the activation functions. Chuanlong Yin , Yuefei Zhu, Jinlong Fei, and Xinzheng He  proposes Recurrent Neural Network based Intrusion Detection System (RNN-IDS) and detected intrusion with minimal false positive count. DBN based IDS  was developed with 97.5% accuracy and it is compared with SVM, DBN accuracy.
4. RELATED WORKS
NSL-KDD dataset was analyzed using WEKA  in this paper. J48, SVM and Naive Bayes classification algorithms are implemented and have concluded that J48 classifier classifies with better accuracy.
Algorithms like Support Vector Machine, Random Forest, Gaussian Naive Bayes and Logistic Regression are applied for analysis . Among them, Random Forest Classifier classifies NSL-KDD with 99%
Hybrid model  was developed for NSL-KDD. After normalization, chi-square method was adapted for feature selection and features with low rank are removed. SVM classifier is used to train, test and validate and it produced results with 98% accuracy.
SVM based Intrusion detection model  was developed. Information gain feature selection with particle swarm optimization was adapted in order to propose FS-PSO-SVM model and obtained 99.8% accuracy.
Principal Component Analysis  was applied to minimize the size of the dataset and it was found SVM works well with high accuracy.
An intelligent intrusion detection system  with two-stage hybrid classification was developed. SVM and ANN were used to detect anomaly and misuse. SVM produced 98.72% result and ANN produced 86%
4.1. DATASET DESCRIPTION
KDD cup 99 dataset contains more number of duplicates. Redundant records will produce inaccurate results while processing. NSL KDD dataset is the processed version of KDD cup 99 dataset and it does not contain duplicates. This dataset is widely for research. There is a lack of availability in benchmark intrusion datasets. This dataset contains both train and test data. 42 features are available and 42nd feature is used to classify the data into normal or attack. Features can be categorized as basic, content, traffic and host . Table I represents the features and its data type. Basic features are duration, protocol_type,service, src_bytes, dst_bytes, flag,land, wrong_fragment and urgent. Content features are hot,num_failed_logins, logged_in, num_compromised, root_shell, su_attempted, num_root, num_file_creations, num_shells, num_access_files, num_outbound_cmds,is_host_login and is_guest_login. Traffic features are count, serror_rate, rerror_rate, same_srv_rate, diff_srv_rate, srv_count, srv_serror_rate, srv_rerror_rate and srv_diff_host_rate. Host features are dst_host_count, dst_host_srv_count, dst_host_same_srv_rate, dst_host_diff_srv_rate, dst_host_same_src_port_rate, dst_host_srv_diff_host_rate, dst_host_serror_rate, dst_host_srv_serror_rate, dst_host_rerror_rate and
Table I. Features and its Types of NSL-KDD Dataset
1 Duration int64
2 protocol_type object
3 Service Object
4 Flag Object
5 src_bytes int64
6 dst_bytes int64
7 Land int64
8 wrong_fragment int64
9 Urgent int64
10 Hot int64
11 num_failed_logins int64
12 logged_in int64
13 num_compromised int64
14 root_shell int64
15 su_attempted int64
16 num_root int64
17 num_file_creations int64
18 num_shells int64
19 num_access_files int64
20 num_outbound_cmds int64
21 is_host_login int64
22 is_guest_login int64
23 Count int64
24 srv_count int64
25 serror_rate float64
26 srv_serror_rate float64
27 rerror_rate float64
28 srv_rerror_rate float64
29 same_srv_rate float64
30 diff_srv_rate float64
31 srv_diff_host_rate float64
32 dst_host_count int64
33 dst_host_srv_count int64 34 dst_host_same_srv_rate float64 35 dst_host_diff_srv_rate float64 36 dst_host_same_src_port_rate float64 37 dst_host_srv_diff_host_rate float64 38 dst_host_serror_rate float64 39 dst_host_srv_serror_rate float64 40 dst_host_rerror_rate float64
41 attack_type Object
42 difficulty_level int64
Features like protocol_type, service,flag and attack_type are categorical data. Land,logged_in, root_shell, num_outbound_cmds,is_host_login and is_guest_login are binary data. Wrong_fragment, urgent, su_attempted, count,srv_count, serror_rate, srv_rerror_rate, same_srv_rate, diff_srv_rate, srv_diff_host_rate, dst_host_count, dst_host_srv_count, dst_host_same_srv_rate, dst_host_diff_srv_rate, dst_host_same_src_port_rate, dst_host_srv_diff_host_rate, dst_host_serror_rate, dst_host_srv_serror_rate
and dst_host_rerror_rate are discrete data.
Duration,src_bytes,dst_bytes,hot,num_failed_logins,num_compromised,num_root, num_file_creations, num_shells and num_access_files are continuous data.
Train data contains 22 types of attacks which are shown in table II. Test data contains 37 types of attacks which are shown in table III. Table IV represents the class of attacks. NSL-KDD dataset contains following types of attacks.
Denial of Service (DoS): Users will be restricted to access services.
Probing: Gaining access to the system through the weak point is probing.
User to Root (U2R): Illegal access to the root.
Remote to Local (R2L): Accessing local system’s data remotely without authorization.
To develop effective IDS, it is essential to identify new attacks, and there is a need to prepare new attack signature.
Table II. Total Number of Attacks and its Types in Train data
Table III. Total Number of Attacks and its Types in Test data normal 9711
Table IV. Classes of Attacks Dos Probe R2L U2R Back ipsweep ftp_write buffer_overflow Land nmap guess_passwd Loadmodule Neptune portsweep Imap Perl Pod satan multihop Rootkit Smurf mscan Phf Ps Teardrop saint Spy Xterm apache2 worm warezclient Sqlattack Mailbomb warezmaster Httptunnel Processtable snmpguess Snmpgetattack Named Udpstorm sendmail Xlock Xsnoop Worm Table V. Frequency Check for Train Data Normal 67343
Table VI. Frequency Check for Test Data Normal 9711
Frequency checks for both train and test data is performed. It is evident from table V and table VI, that DoS attack is high in both train and test data.
5. MODEL SETUP
The analysis of data to categorize attacks is done using Python. As the first step, necessary library packages are imported; next NSL-KDD dataset is imported. Basic exploratory data analysis of dataset is done. Frequency table is constructed for continuous features. Histogram is generated for the features to find the distribution of attacks. Feature Transformation is done by feature encoding, feature scaling, label encoding and label binarizer. Figure 1 shows the importance of the features. All features are assigned with score based on the correlation of the particular feature with other features. Among the features, same_srv_rate contributes more with score 0.36 , service_ecr_i contributes with score 0.10 etc., Feature with highest score is the most important feature. Visualization of dataset is done using PCA. It is difficult to visualize the entire data because of its size. To overcome this problem PCA is applied and four PCA components are generated to visualize data using scatter 3D plot. Figure 2 represents data based on first three components PCA1,PCA2 and PCA3. Figure 3 represents data based on PCA2, PCA3 and PCA4 components. Each color in the 3D plot represents each attack. This paper deals NSL-KDD dataset with four models. From these four models, the best classifier which is suitable to handle NSL-KDD dataset is identified with high accuracy, precision and F1Score. Figure 6 shows four models which are used in this paper.
Fig. 1 Feature Importance Plot
Fig. 2 Scatter 3D Plot of NSL-KDD Dataset for Principal Components 1, 2 and 3
Fig. 3 Scatter 3D Plot of NSL-KDD Dataset for Principal Components 2, 3 and 4
5.1. LOGISTIC REGRESSION
The name logistic regression may represents regression but it is a classification algorithm.
Logistic Regression estimates discrete values. It can classify data into 0 or 1, yes or no, true or false. The output values always lies between 0 and 1. Classification can be either binary or multi class classification.
If the target variable is categorical, logistic regression can be applied.
This is the equation of a straight line. Here m represents slope, x represents data points and c represents intercept. Slope is used for stretching the curve and intercept is used to move up and down through the graph.
The sigmoid or logistic function is denoted as
If –y=∞ then If y=-∞ then If y=0 then
There are various methods for denoting equation for a straight lie h( + x (3)
h( + x (4)
y= x+b (5)
Fig. 4 Sigmoid Function 
Fig. 4 represents sigmoid function. Threshold value can be set to 0.5. If predicted value (P) is 0.8 and the threshold value is 0.5, then it belongs to class 1 or positive. If predicted value (P) is 0.2 and the threshold value is 0.5, then it belongs to class 0 or negative. Log loss function is used to calculate the error.
Log loss function is to minimize large negative number. Gradient descent is opted to optimize the loss.
The advantage of using logistic regression is, it can be used to solve multiclass problems and it is resistant to over fitting.
5.2. DECISION TREE CLASSIFIER
Decision Tree classifier  is like tree structure which consists of branches and nodes. Branch serve as decision rules, nodes serves as outcome.
Root : This acts as the parent node in the tree.
Leaf : These nodes depend on root node and it is the outcome of other nodes.
Splitting: Subdivision of tree into sub nodes based on particular condition.
Branch Tree: After splitting, the separated tree is branch tree.
Pruning: Removal of unwanted branches.
Over fitting is possible in decision tree. Attribute Selection Measure (ASM) is essential to find the best feature in the dataset. Division of nodes based on best attribute is done recursively. Entropy is used to check whether it is pure set or not. Information Gain is used to measure the changes in entropy after subdivision of dataset. If entropy is less, then information gain will be higher.
5.3. RANDOM FOREST CLASSIFIER
Random Forest classifier  contains many decision trees and it takes the average of them to get accurate results. Over fitting is avoided in Random Forest classifier since, there are many trees. It works based on majority of votes. It can handle voluminous dataset. Over fitting is avoided, hence it produces accurate results.
Yoav Freund and Robert Schapire proposed Adaboost (Adaptive Boosting) in 1996 . Adaboost selects and trains the subset in a random manner. Higher weights are assigned to the data which is classified incorrectly. Classifier with higher weights is the most accurate classifier. This iteration will be done till it reaches maximum esitmators.
XGboost is also called as Extreme Gradient Boosting . Overfitting can be avoided when using XGboost. Cross-validation is enabled by default in this algorithm. It was proposed by Tianqi Chen, Ph.D student, University of Washington. XGboost converts slow learners into fast learners. General parameters, booster parameters and learning task parameters are available for this algorithm.
5.6.MULTI LABEL CLASSSIFICATION
Multi label classification problem can be handled using classifier chains. It is the chain of binary classifiers. A chain of binary classifiers Classifier1, Classifier2, . . . , Classifier n is constructed. This chaining method is called classifier chains (CC) .This helps to classify the attacks.
5.7. MODEL GENERATION
5.7.1. MODEL 1:
Dimensionality reduction is done using Principal Component Analysis (PCA) . After that, Logistic Regression, Random Forest Classifier and Decision Tree Classifier are applied to generate the model.
After feature transformation, the data is applied to classifiers like Logistic Regression, Random Forest Classifier, Decision Tree Classifier, Adaboost and XGBoost.
NSL-KDD has different kinds of attacks and it is a Multi-label classification problem. A classifier chain is applied to deal with multi label classification.
Deep learning algorithm is applied in this method. Basic neural network is used to serve the purpose.
Local Interpretable Model-agnostic Explanations (LIME)  is a python library that is used to explore the model. Fig. 5 depicts the prediction probabilities of the attacks which are represented in numbers, using LIME. Number 14 is the attack type. Features which contribute more to that attack are listed. Features like dst_host_serror_rate, dst_host_srv_serror_rate and flag_SF contributes more to perform attack number 14.
Fig. 5 LIME –Prediction Probabilities
LIME package explains the predictions done by various machine learning algorithms. Importance of features is identified using plot and LIME library. Based on this the model is generated.
Fig. 6 Work flow of Machine Learning and Deep Learning Classifiers
6. RESULTS & DISCUSSION
Model 1: PCA with Classifiers
Table VII. Accuracy and Misclassification Rate of the Classifiers Algorithm Training
Logistic Regression 88.8% 88.6% 11.3%
Random Forest 99.9% 98.7% 1.2%
Decision Tree 99.9% 97.9% 2.0%
Random forest algorithm produces 98.7% accuracy. Misclassification rate is 1.2% which is low when compared to logistic regression and decision tree algorithms.
Model 2: Transformed data with Classifiers
Table VIII. Accuracy and Misclassification Rate of the Transformed Classifiers Algorithm Training
Logistic Regression 98.8% 98.7% 1.2%
Random Forest 99.9% 99.7% 0.2%
Exploratory Data Analysis
Visualization using PCA
PCA Multi label
Neural Network Logistic Regression
Decision Tree Classifier
Random Forest Classifier
Decision Tree Classifier
Random Forest Classifier
Decision Tree 99.9% 99.6% 0.3%
Adaboost 99.9% 99.8% 0.1%
XGBoost 99.7% 99.6% 0.3%
Adaboost algorithm performs better with 99.8% accuracy when compared to Random Forest, XGBoost, Decision Tree and Logistic regression. Misclassification rate of Adaboost is 0.1%.
Model 3: Transformed data with Multi-label classifier (Classifier Chain) Table IX. Accuracy and Misclassification Rate of Multi Label Classifier
Algorithm Training Accuracy
Random Forest 99.9% 99.6% 0.003%
99.6% accuracy is attained by applying Random forest Multi label classifier. Misclassification rate
Model 4: Transformed data with Deep Learning (Deep neural network) Table X. Accuracy and Misclassification Rate of Deep Neural Network
Algorithm Training Accuracy
Misclassification Rate Deep Neural
99.4% 99.2% 0.7%
Basic network was applied as a deep learning approach and 99.2% accuracy is gained. 0.7%
misclassification rate is attained. Fig. 7 shows the increasing level of accuracy of the model. Figure 8 shows the decreasing level of loss of the model.
Fig. 7 Accuracy of Neural Network Model
Fig. 8 Loss of Neural Network Model
Among the four methods, Adaboost algorithm works well with 99.8% accuracy and with less misclassification rate (0.1%)
7. PERFORMANCE METRICS & EVALUATION
After model generation, the evaluation of performance of the particular model must be measured.
Performance of a model depends on number of True Positives (TP), True Negatives (TN), False Positives (FP) and False Negatives (FN). Accuracy is a generic metric to determine the performance of the model.
To handle imbalanced distribution of classes, performance metric like Recall, Precision and F1Score is required. Recall is also known as sensitivity. If the model has large number of False Negatives, then Recall is the best measure to handle it. Recall is used to calculate correctly classified positives from actual positives.
Precision is used to calculate number of positives which are correctly classified from predicted positives. If the model contains large number of False Positives, then Precision can be used.
Precision = (8)
F1 score is used to provide a balance between precision and recall.
F1 Score= (9)
Model 1: PCA with Classifiers
Table XI. F1 Score, Precision and Recall of the Classifiers Algorithm F1 Score Precision Recall Logistic Regression 91.4% 94.6% 88.6%
Random Forest 98.7 % 98.8% 98.7%
Decision Tree 97.9% 97.9% 97.9%
Among Logistic Regression , Random Forest and Decision Tree classifiers, Random Forest classifier has highest F1 Score (98.7%) and Precision (98.8%).
Model 2: Transformed data with Classifiers
Table XII. F1 Score, Precision and Recall of the transformed Classifiers Algorithm F1 Score Precision Recall
Logistic Regression 98.8% 99.0% 98.7%
Random Forest 99.7 % 99.7% 99.7%
Decision Tree 99.6% 99.6% 99.6%
Adaboost 99.8% 99.8% 99.8 %
XGBoost 99.6% 99.7 % 99.6 %
Among Logistic Regression , Random Forest and Decision Tree, Adaboost and XGBoost classifiers, Adaboost classifier has highest F1 Score (99.8%) and Precision (99.8%).
Model 3: Transformed data with Multi-label classifier (Classifier Chain)
Table XIII. F1 Score, Precision and Recall of Multi-label Classifier (Classifier Chain) Algorithm F1 Score Precision Recall
Random Forest 99.6 % 99.7% 99.6%
Multi-label classifier (Classifier Chain) which uses Random forest produces 99.6% F1 Score and 99.7% Precision.
Model 4: Transformed data with Deep Learning (Deep neural network) Table XIV. F1 Score, Precision and Recall of Deep Neural Network
Algorithm F1 Score Precision Recall Deep Neural Network 99.3 % 99.4% 99.2%
Deep learning neural network produces 99.3% F1Score and 99.4% precision. Among the four methods Adaboost classifier has highest F1Score (99.8%) and Precision (99.8%).
8. CONCLUSION & FUTURE ENHANCEMENT
Best intrusion detection system must generate high accurate results and it should have lower false alarm rate. Adaboost algorithm performs well with 99.8% accuracy, 99.8% F1Score and 99.8% Precision. Hence the best classifier for NSL-KDD dataset is Adaboost. In future, intelligent IDS should be developed in order to identify active threats while data is streaming. Soft computing techniques like genetic algorithms, fuzzy and nature-inspired optimization can be used to provide better accurate results with less false rate.
An effective response system should be build to respond to the attacks which are already happened
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