Since denial-of-service (DoS) attacks are a major threat to e-commerce, waves of DoS attacks against prominent Web pages gained wide publicity. Typically DoS attacks target Web sites with bogus requests for data in order to slow or block legitimate users from accessing services. In recent years, distributed denial-of-service (DDoS) attacks have been used, which expand the vulnerability of Web sites. Attackers use hundreds or thousands of compromised systems in order to harm commercial Web sites. Attackers use different ways to harm their victims. They manipulate the target networks or target server servers directly by using lacks of protocols and standards to force failures and shut-downs. Or, they try to deplete resources like bandwidth, memory, or processing capacities. Attackers try to hinder or interfere with legitimate users with both strategies. Damages from DDoS attacks can range from inconvenience for legitimate users and customers to a lack of reliability for the site and—finally—to a shutdown of the server and some delay until web services are continued. This is a severe threat for all companies involved in e-commerce, and managing that risk is important to offer secure and reliable services. Therefore, management must take actions of prevention, detection and mitigation in order to protect their Web services.
DDoS Attacks Detection of Application Layer for Web Services using Information based Metrics