Denial of Service AttackDenial of Service Attack

발표자 : 전지훈

What is Denial of Service Attack?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 DoSGoal 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…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 AttackSymptoms 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 emails received

Prevention of DoS AttackPrevention of DoS Attack

Firewalls

Switches

Routers

Intrusion-prevention systems (IPS)

DDoS AttackDDoS 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 AttackDDoS Attack

Attacker

Master(Handler)

Agent

Master(Handler)

Master(Handler)

AgentAgent AgentAgent Agent Agent

Target

Advantages of DDoS AttackAdvantages 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

ReferenceReference

http://en.wikipedia.org/wiki/DoS

http://www.cert.org/

Any Question?

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