The Internet has become a necessity in today's digital world, and making it secure is a pressing concern. Hackers are investing ever-increasing efforts to compromise Internet nodes with novel techniques. According to Forbes, every minute, $ 2,900,000 is lost to cybercrime. A common cyber-attack is Denial of Service (DoS) or Distributed Denial of Service (DDoS) attacks, which may bring a network to a standstill, and unless mitigated, network services could be halted for an extended period. The attack can occur at any layer of the OSI model. This thesis focuses on SYN Flood DoS/DDoS attacks, also known as TCP Flood attacks, and studies the use of artificial neural networks to detect the attacks. Specific neural network models used in this thesis are the Gated Recurrent Units (GRU), the Long Short-Term Memory (LSTM), and a semi-supervised model on label propagation. All neural network models detect attacks by analyzing the individual hexadecimal values in the packet header. A novelty of the approach followed in this thesis is that the neural networks do not consider the lexical values of the network packet (MAC addresses, IP addresses, and port numbers) as input features in their traffic analysis. Instead, the neural network models are designed and trained to detect malicious traffic based on the time pattern of TCP flags. The neural networks base their analysis of traffic on time-sequenced patterns. An important hyperparameter discussed in this paper is the size of the lookup window, that is, the number of past packets the model can access to predict the next packet. Evaluation results based on datasets presented in this thesis show that the accuracies of the GRU, CNN/LSTM, and label propagation models are 81%, 93%, and 96%, respectively.

Library of Congress Subject Headings

Denial of service attacks--Prevention; Internet--Security measures; Neural networks (Computer science)

Publication Date


Document Type


Student Type


Degree Name

Computer Engineering (MS)

Department, Program, or Center

Computer Engineering (KGCOE)


Andres Kwasinski

Advisor/Committee Member

Amlan Ganguly

Advisor/Committee Member

Bruce Hartpence


RIT – Main Campus

Plan Codes