Denial of Service Attack 발표자 : 전지훈

What is Denial of Service Attack?  Denial of Service Attack = DoS Attack  Service attacks on a Web server floods it with bogus requests for pages.  The server spends so much time trying to process these requests that it can't respond to legitimate requests and may crash.

Goal of DoS  To flood a network, thereby preventing legitimate network traffic  To Disrupt connections between machines, thereby preventing access to a service  To prevent a particular individual from accessing a service  To disrupt service to a specific system or person

DoS Attack does…  Consumption of computational resources, such as bandwidth, disk space, or processor time  Disruption of configuration information, such as routing information.  Disruption of state information, such as unsolicited resetting of TCP sessions.  Disruption of physical network components.  Obstructing the communication media between the intended users and the victim so that they can no longer communicate adequately

Symptoms of DoS Attack  Unusually slow network performance  Unavailability of a particular web site  Inability to access any web site  Dramatic increase in the number of spam s received

Prevention of DoS Attack  Firewalls  Switches  Routers  Intrusion-prevention systems (IPS)

DDoS Attack  Distributed Denial of Service Attack  Multiple compromised systems flood the bandwidth or resources of a targeted system, usually one or more web servers

DDoS Attack Attacker Master (Handler) Agent Master (Handler) Master (Handler) Agent Target

Advantages of DDoS Attack  Multiple machines can generate more attack traffic than one machine  Multiple attack machines are harder to turn off than one attack machine  Behavior of each attack machine can be stealthier, making it harder to track down and shut down

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