Denial Of Service Attack

Denial Of Service Attack

Submitted by Srikanth on Friday, 7 November 200819 Comments

Its Real,On February 6th, 2000, Yahoo portal was shut down for 3 hours. Then retailer Buy.com Inc. (BUYX) was hit the next day, hours after going public. By that evening, eBay (EBAY), Amazon.com (AMZN), and CNN (TWX) had gone dark. And in the morning, the mayhem continued with online broker E*Trade (EGRP) and others having traffic to their sites virtually choked off.

What is a Denial Of Service Attack?

A denial of service attack (DOS) is an attack through which a person can render a system unusable or significantly slow down the system for legitimate users by overloading the resources, so that no one can access it.
If an attacker is unable to gain access to a machine, the attacker most probably will just crash the machine to accomplish a denial of service attack.

Types of denial of service attacks

There are several general categories of DoS attacks.Popularly, the attacks are divided into three classes:

bandwidth attacks,
protocol attacks, and
logic attacks

What is Distributed Denial of Service Attack?

An attacker launches the attack using several machines. In this case, an attacker breaks into several machines, or coordinates with several zombies to launch an attack against a target or network at the same time.
This makes it difficult to detect because attacks originate from several IP addresses.
If a single IP address is attacking a company, it can block that address at its firewall. If it is 30000 this is extremely difficult.

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19 Comments »

Blaster(Ash) said:

Yeah, recently DDOS attack is getting too famous. And they are using a technique called REFLECTIVE AMPLIFICATION. Do you know anything bout this technique?

- 12 November 2008 at 8:16 pm

Srikanth (author) said:

@ blaster

Recursive amplification

This type of attack uses IP address spoofing, a type of impersonation technique, where
the attacker transmits packets with a forged source IP address rather than its own. The attack also exploits DNS servers that allow open recursion. Recursion is a method of processing a DNS query in which a name server pursues the query for a client at (typically) the authoritative name server for the name. When recursion is performed for any client as opposed to a trusted set of clients, a name server is said to be an open recursive server. Finally, the attack uses amplification, where the attacker sends a small request with the expectation of invoking a much larger response.

- 13 November 2008 at 6:59 am

Slim0123 said:

Hey Srikanth, can you let we people, be educated, about how to make an army of zombie computers so as to successfully implement a ddos attack???

- 31 December 2008 at 12:47 am

sonu said:

is there any software available for dos attack
if yes send me link

- 24 January 2009 at 2:12 pm

XXX said:

there are tools available, but read the legislation about Cyber crime of the country in which u perform DDos or DoS attack.

u could be behind the jail for 10 year for DoS attack as per guideline of U.S.A Cyber crime rules.

so think before doing anything like shit!!!!!!!!!!!!

- 8 April 2009 at 11:44 am

amit said:

it’s too old bro

- 10 April 2009 at 10:29 pm

jackiy said:

HI
plesa send me link
thanks

- 26 April 2009 at 12:54 am

Pyrobyte said:

Didn’t websites block this feature a long time ago? I don’t think it is possible these days… Is it?

- 13 May 2009 at 7:03 am

Srikanth (author) said:

@ Pyrobyte

DOS attacks are still possible today.

- 13 May 2009 at 8:43 am

Pyrobyte said:

Hm. I thought I read somewhere that they can no longer be executed. Well, thanks.

- 16 May 2009 at 10:23 pm

yash said:

its good……..
but more good articles at

- 18 May 2009 at 7:56 am

Sunny said:

Hi,
Can anyone teach me hacking from basics..
if yes send me mail..
sunnyzende@hotmail.com
pls..

- 10 June 2009 at 9:06 am

Mafia said:

Srikanth you told me that one can forge his IP……….
How can one do that?

- 4 July 2009 at 9:23 pm

Kickass said:

hii guyss

please tell me that about DDos attacks and how it works..??

how can i use it in game counter strike , i want to crush bloody fuckers servers.
please temme fast

- 12 July 2009 at 1:35 pm

selva said:

hiiiiii dude o need a help from u
i know the ip of the victim
i tried the fewq tips to hack the hard sik but i cant
how to hack the hard disk of the victims
just say the latest tips nowwwwwwwwwww

- 16 August 2009 at 5:14 am

rickyfederer said:

hi shri..tell m how do d terrorists use d various technological aspects…..xplain vit an example on 26/11 mumbai attacks………….thnx geeky…

- 10 October 2009 at 4:51 am

amjad said:

always learn each and every thing for a good use soooooooooooo it well give you the power of learning okay dude i want to know how the an attacker can use 30000 ip as u mentioned above???????????? plz explain it thank alot

- 15 January 2010 at 7:28 pm

amjad said:

my other question is that how to by pass the firewall means if i got the ip and i want to access that user..

thanks in advance ..thankkkkkkkks

- 15 January 2010 at 7:31 pm

Srikanth (author) said:

@ amjad

Hacker first compromises an entire network of computers which is vulnerable. There he installs the DOS tools and initiates the attack. In this way he can attack from several computers and hence several IP addresses at a time.

- 21 January 2010 at 3:53 pm