Countering Distributed Denial of Service (DDoS) attacks is becoming ever more challenging with the vast resources and techniques increasingly available to attackers. In our project, we consider sophisticated attacks that are protocol-compliant, non-intrusive, and utilize legitimate application-layer requests to overwhelm system resources. We identify three basic elements of a test scenario:
• The attack,
• The legitimate traffic,
• The network topology including services and resources.
The attack dimension defines the attack type and features, while the legitimate traffic dimension defines the mix of the background traffic that interacts with the attack and may experience a denial-of service effect. The topology/resource dimension describes the limitations of the victim network that the attack targets or interacts with. It captures the physical topology, and the diversity and locations of important network services.
We characterize application layer resource attacks as either request flooding, asymmetric, or repeated one-shot, on the basis of the application workload parameters that they exploit.
To protect servers from these attacks, we propose a counter-mechanism that consists of a suspicion assignment mechanism and a DDoS-resilient scheduler, DDoS Shield .
In contrast to prior work, our suspicion mechanism assigns a continuous value as opposed to a binary measure to each client session, and the scheduler utilizes these values to determine if and when to schedule a session's requests
Apache HTTP server 2.2
1 GB RAM
60 GB Hard Disk