M.Sc. Tezi Görüntüleme

      In the recent epoch of the 20th century, the invention of PCs had been a revolution for the mankind. But just after a little while, when the need of sharing the information increased, computer networks that consist of multiple PCs, took the place of local PC. Computer networks including different systems brought a lot of problems itself because of opening the doors of local PCs to the world. How to provide system security is still one of the most important problem that is insolvable.

      The way of providing security is to understand how to implement the methods putting the systems in bad situtations. Nowadays malicious software and different attack methods threaten system security. For this reason, DOS and DDOS attacks threating the security of the systems connected to the network are analyzed in this thesis. DOS attacks purpose dropping the victim's bandwidth by sending a lot of packets or preventing the access of clients to the services provided by victim. In this thesis, different kinds of DOS and DDOS attacks are analyzed and implemented. To increase the efficiency of the attack, it's been worked to choose the most suitable victim. So that monitoring the activity of PCs in the LAN is done. At the same time, for providing the data communication secure between the attacker and the dameons in the DDOS attacks, various workings are made in the data security area. DES symmetric algorithm at the bit level and the data hiding with 24 bit picture files for the steganography are implemented.

      Day and day vulnerabilities of the systems increased so much and that made the security more important. Attacks and the effects of them which are analyzed in this thesis, will give you an idea on providing the security to the system and avoiding the vulnerabilities that create new kinds of attacks.

      Keywords: DOS, DDOS, IDS, DES Symmetric Algorithm, Data Monitoring, Steganography