Sharif Digital Repository

Web servers and web applications are susceptible to different attacks. In order to detect web-based attacks Intrusion detection systems (IDS) should be equipped with a large number of signatures. Unfortunately various types of web threats are increasingly growing and so detection and prevention of all these new and old attacks is exhaustive and really difficult.This thesis represents a designed system for intrusion detection that uses different techniques to discover vulnerabilities with derived patterns and also some user behavior based attacks against web applications. This was done by using new dataset which was generated by new log file.The primary objective of this thesis shows the... 

Using the achievements of differential geometry an extended form of descent equations is worked out which leads to a set of modified consistent anomalies. A gauge invariant partition function is also defined for gauge theories with the standard quantization results. It is shown that the (extended) descent equations and consequently the (modified) consistent anomalies and Schwinger terms can be extracted from this modified partition function naturally. Moreover Translation-invariant products are discussed in the setting of α-cohomology and it is shown that loop calculations of Translation-invariant quantum field theories are entirely determined by α-cohomology class of star product in all... 

Generating realistic network traffic serves capacity planning, traffic engineering, understanding internet service performance and anomaly detection. A useful traffic generator must generate characteristics in flows and packets, and add known internet anomalies to legitimate traffic. In this dissertation, we develop a tool for generating realistic and anomalous traffic. This generator can generate traffic in a scalable, reproducible and stochastic manner. Two methods are proposed for this purpose. In the first method, the traffic is generated according to statistical distribution of packets and flow charactristics. In the second method, traffic is generated by modeling the behavior of... 

Generating real traffic and attacks for network equipment and applications are not yet considered a clear straight forward subject. To overcome this issue, we produce real traffic and then add some vulnerability attacks to it. This is an important step towards achieving security tests or evaluation methods which let us examine or assess intrusion detection (IDSs) features of a system.In this dissertation, we generate legitimate and anomalous traffic beside some attacks. Our study yields an implementation which is tested in real environment. We introduce a substantial method to generate DDoS attack in network and transport layers. We develop a software tool for this purpose. The performance... 

In recent years, molecular communications have received considerable attentions for communication between nano-machines. In this communication scheme, which uses molecules as information carriers, nano transmitter and receiver are in distance apart of nano meter to meter and information is encoded into type, concentration or releasing time of molecules. Since nano transmitter and receiver can do very simple operations, such as adding, sensing, and etc., for more complicated operations, a network of nano transceivers is required. In this thesis, a small scale imaging of an abnormality in the environment is investigated. To this end, a network of sensors is assumed to be placed in the...