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Methods of the DDoS attacks

Although there are different types of attack methods, DDoS attacks can generally be divided
into two categories:

• Volumetric attacks: Flood attacks saturate the bandwidth of the network and
infrastructure (e.g., UDP, TCP SYN, and ICMP). It causes a high volume traffic on the
targeted server and creates expensive damage to service consequently, users get lost
access to the service.
• Attacks on the application layer: These attacks are designed to meet specific services
and to exhaust their resources (HTTP, DNS). They use less bandwidth, and are more
difficult to detect. The DDoS attack on the application layer makes all services remain
inaccessible.
• The Slowloris software:The Slowloris software is unremarkable in comparison to most
flooding tools. It keeps many connections open and continues them unlock for a long
time. It keeps connections open to the targeted web server and sends a partial request.
At a later, it sends an HTTP request in addition but never completes the request. Thus,
the web server keeps connections open.

DDoS attacks annually increased by 20% to 45%; DDoS attacks at the application layer might
even increase to the "triple digits”. There is a clear trend of DDoS attacks on the application
layer and it is unlikely that this trend will reverse.

51 Cyber Warnings E-Magazine – July 2015 Edition
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