HI all
In this tutorial you will know what is Denial Of Service
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A Denial Of Service is an attack through which a person can a system unusable or slow down for legitimate users by overload to it's process
If an attacker is disable to get access to any machine, the attacker will most likely crash the machine to with a denial of service. The goal of denial of service is not to gain access to unauthorized machine or data
Dos Attacks Types
Smurf
Buffer Overflow Attack
Ping Of Death
Teardrop
Syn Attack
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Smurf attack:
The attacker generates a large amount of icmp echo (Ping) to a network broadcast with a spoofed source IP set to a victim host the result will be lots of ping replies flooding the spoofed host
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Buffer Overflow Attack
Buffer overflow occurs when the program writes more information in buffer than space.
exampler:
Sending email message who have attachment with 256 character file names can cause buffer overflow
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Ping Of Death Attack
The attacker sends an ip packet larger than 65536 bytes allowed by the ip protocol
Fragmentation allows a single ip packet to be broken down into smaller segment the opreating system unable to handle these large packets therefore opreating system freeze, reboots or crash.
the identy of the attacker sending the oversized packet can be easily spoofed
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Teardrop attack
Ip requires that a packet that is too large for the next router to handle be divided into fragments. The attacker's ip puts a confusing offset value in the second or later fragment if receving opreating system is unable to aggregate the packets accordingly it can crash the system
It is udp attack which uses overlapping offset fields to bring down hosts
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Syn Attack
The attacker send bogus tcp syn request to a victim. Syn attack exploit the three way handshake. Malicious flooding by large volumes of Tcp Syn packets to the victim's system with spoofed source ip addresses can cause D.o.s