--Originally published at Computer and Information Security

Hi reader! I hope you are enjoying my posts, this time I am going to talk about DoS (Denial of Service). So, in simple words, this is a common and most used technique by hackers and people that want to see the world burn, it occurs when an attacker takes action that prevents legitimate users from accessing targeted computer systems, devices or other network resources.

This type of attacks usually send a lot of information, data or traffic to a server, through a bunch of other helpers called zombies, in order to staturate the network in that server or victim resources and make it impossible for the victim to use the service properly.

Some characteriztics of this attack are:

• Degradation in network performance, especially when attempting to open files stored on the network or accessing websites.
• Inability to reach a particular website.
• Difficulty in accessing any website.
• A higher than usual volume of spam e-mail.
• Hard to play a videogame since there is a lot of lag or traffic from the nework.

To restore the normal use of the service in those cases, a reboot of the system fixes the DoS attack, but there are a lot of different types of this attack that can more difficult to recover from:

• Buffer overflow attack: Is a catchall description most commonly applied to DoS attacks that send more traffic to a network resource than was ever anticipated by the developers who designed the resource. One example of such an attack sent, as email attachments, files that have 256-character file names to recipients using Netscape or Microsoft email clients; the longer-than-anticipated file names were sufficient to crash those applications.
• DDoS attack: The attacker may use computers or other network-connected devices that have been infected by malware and made part of a botnet. Distributed denial-of-service attacks, especially those using botnets, use command-and-control (C&C)
  
  
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