What is denial of service attack?

Denial of service (DOS)

In computing, a denial-of-service (DoS) attack is an attempt to make a machine or network resource unavailable to its intended users, such as to temporarily or indefinitely interrupt or suspend services of a host connected to the Internet.

Simple DoS attack is performed from single computer where attacker fluds request over network to a specific server by means of various protocols. a simple DoS attck would consist of thousands of ping requests which will overflow the buffers of servers or target leading it to crash or bluescreen errors.

Types:

Volume Based AttacksIncludes UDP floods, ICMP floods, and other spoofed-packet floods. The attack’s goal is to saturate the bandwidth of the attacked site, and magnitude is measured in bits per second (Bps).

Protocol AttacksIncludes SYN floods, fragmented packet attacks, Ping of Death, Smurf DDoS and more. This type of attack consumes actual server resources, or those of intermediate communication equipment, such as firewalls and load balancers, and is measured in Packets per second.

Application Layer AttacksIncludes low-and-slow attacks, GET/POST floods, attacks that target Apache, Windows or OpenBSD vulnerabilities and more. Comprised of seemingly legitimate and innocent requests, the goal of these attacks is to crash the web server, and the magnitude is measured in Requests per second.

Tools:


1. LOIC (Low Orbit Ion Canon)

LOIC is one of the most popular DOS attacking tools freely available on the Internet. This tool was used by the popular hackers group Anonymous against many big companies’ networks last year. Anonymous has not only used the tool, but also requested Internet users to join their DDOS attack via IRC.
It can be used simply by a single user to perform a DOS attack on small servers. This tool is really easy to use, even for a beginner. This tool performs a DOS attack by sending UDP, TCP, or HTTP requests to the victim server. You only need to know the URL of IP address of the server and the tool will do the rest.
You can see the snapshot of the tool above. Enter the URL or IP address and then select the attack parameters. If you are not sure, you can leave the defaults. When you are done with everything, click on the big button saying “IMMA CHARGIN MAH LAZER” and it will start attacking on the target server. In a few seconds, you will see that the website has stopped responding to your requests.

This tool also has a HIVEMIND mode. It lets attacker control remote LOIC systems to perform a DDOS attack. This feature is used to control all other computers in your zombie network. This tool can be used for both DOS attacks and DDOS attacks against any website or server.
The most important thing you should know is that LOIC does nothing to hide your IP address. If you are planning to use LOIC to perform a DOS attack, think again. Using a proxy will not help you because it will hit the proxy server not the target server. So using this tool against a server can create a trouble for you.
Download LOIC here:

Download

  2. XOIC

XOIC is another nice DOS attacking tool. It performs a DOS attack an any server with an IP address, a user-selected port, and a user-selected protocol. Developers of XOIC claim that XOIC is more powerful than LOIC in many ways. Like LOIC, it comes with an easy-to-use GUI, so a beginner can easily use this tool to perform attacks on other websites or servers.

In general, the tool comes with three attacking modes. The first one, known as test mode, is very basic. The second is normal DOS attack mode. The last one is a DOS attack mode that comes with a TCP/HTTP/UDP/ICMP Message.
It is an effective tool and can be used against small websites. Never try it against your own website. You may end up crashing your own website’s server.
Download XOIC: http://sourceforge.net/projects/xoic/
3. HULK (HTTP Unbearable Load King)

HULK is another nice DOS attacking tool that generates a unique request for each and every generated request to obfuscated traffic at a web server. This tool uses many other techniques to avoid attack detection via known patterns.
It has a list of known user agents to use randomly with requests. It also uses referrer forgery and it can bypass caching engines, thus it directly hits the server’s resource pool.
The developer of the tool tested it on an IIS 7 web server with 4 GB RAM. This tool brought the server down in under one minute.
Download HULK here: http://packetstormsecurity.com/files/112856/HULK-Http-Unbearable-Load-King.html
4. DDOSIM—Layer 7 DDOS Simulator

DDOSIM is another popular DOS attacking tool. As the name suggests, it is used to perform DDOS attacks by simulating several zombie hosts. All zombie hosts create full TCP connections to the target server.
This tool is written in C++ and runs on Linux systems.
These are main features of DDOSIM

• Simulates several zombies in attack
• Random IP addresses
• TCP-connection-based attacks
• Application-layer DDOS attacks
• HTTP DDoS with valid requests
• HTTP DDoS with invalid requests (similar to a DC++ attack)
• SMTP DDoS
• TCP connection flood on random port

Download DDOSIM here: http://sourceforge.net/projects/ddosim/
Read more about this tool here: http://stormsecurity.wordpress.com/2009/03/03/application-layer-ddos-simulator/
5. R-U-Dead-Yet

R-U-Dead-Yet is a HTTP post DOS attack tool. For short, it is also known as RUDY. It performs a DOS attack with a long form field submission via the POST method. This tool comes with an interactive console menu. It detects forms on a given URL and lets users select which forms and fields should be used for a POST-based DOS attack.
Download RUDY: https://code.google.com/p/r-u-dead-yet/
6. Tor’s Hammer

Tor’s Hammer is another nice DOS testing tool. It is a slow post tool written in Python. This tool has an extra advantage: It can be run through a TOR network to be anonymous while performing the attack. It is an effective tool that can kill Apache or IIS servers in few seconds.
Download TOR’s Hammer here: http://packetstormsecurity.com/files/98831/
7. PyLoris

PyLoris is said to be a testing tool for servers. It can be used to perform DOS attacks on a service. This tool can utilize SOCKS proxies and SSL connections to perform a DOS attack on a server. It can target various protocols, including HTTP, FTP, SMTP, IMAP, and Telnet. The latest version of the tool comes with a simple and easy-to-use GUI. Unlike other traditional DOS attacking tools, this tool directly hits the service.
Download PyLoris: http://sourceforge.net/projects/pyloris/
8. OWASP DOS HTTP POST

It is another nice tool to perform DOS attacks. You can use this tool to check whether your web server is able to defend DOS attack or not. Not only for defense, it can also be used to perform DOS attacks against a website.
Download here: https://code.google.com/p/owasp-dos-http-post/
9. DAVOSET

DAVOSET is yet another nice tool for performing DDOS attacks. The latest version of the tool has added support for cookies along with many other features. You can download DAVOSET for free from Packetstormsecurity.
Download DavoSET: http://packetstormsecurity.com/files/123084/DAVOSET-1.1.3.html
10. GoldenEye HTTP Denial Of Service Tool

GoldenEye is also a simple but effective DOS attacking tool. It was developed in Python for testing DOS attacks, but people also use it as hacking tool.
Download GoldenEye: http://packetstormsecurity.com/files/120966/GoldenEye-HTTP-Denial-Of-Service-Tool.html

How to install PROCESSING in ubuntu

Processing is an open source computer programming language and integrated development environment (IDE) built for the electronic arts, new media art, and visual design communities with the purpose of teaching the fundamentals of computer programming in a visual context, and to serve as the foundation for electronic sketchbooks.
           If you are an electronics enthusiastic and deal with arduino this is for you.
I assume you have basic knowledge of linux, if not you can always head over to tutorialspoint. Make sure you know how to use sudo.

 First, download Processing. On Ubuntu 12.04, the 64-bit architecture is appropriate. It downloads as a .tgz archive, typically into the Downloads folder in your Home folder. You can extract the archive by double-clicking in Ubuntu’s file system browser or extract it from the command line in a Terminal with tar -xf processing-2.2.1-linux64.tgz. Once you have extracted the folder processing-2.2.1, you’ll need to decide where to locate it. I created a new directory, Developer, in my Home Folder, and moved Processing to it just by dragging and dropping. You could also install Processing in the /opt/ folder, though this requires an admin account and use of the Terminal.
If Processing just ran out of the box, you could double-click and run the processing script in the processing-2.2.1 folder or point a Terminal to the folder and type ./processing and hit return (the latter is the approach I recommend). That is unlikely to work because of incompatibilities with the downloaded version of Java in Processing and the default Java environment on Ubuntu. You can resolve the incompatibilities in two steps: installing a new version of Java and adjusting Processing’s directory structure. After reading the supported platforms page in the Processing Wiki, I decided that it made the most sense to install Oracle Java 7.

Installing Oracle Java 7

Information on issues with Java can be found in Ubuntu Help. Take a moment to read the section on Oracle Java 7. Because of licensing issues, Java has to be downloaded and installed from Oracle. Fortunately, there is a tool to simplify this process at webupd8.org. The documentation is clear and simple, and I leave you to it. Once you’ve installed Java, run the Java environment variables installer, too. FWIW, here is my command history for this process:
java -version
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java7-installer
java -version
sudo apt-get install oracle-java7-set-default
update-alternatives --display java


Adjustments to Processing

Once you have Oracle Java 7 installed and set as the default version of Java in Ubuntu, you’ll still need to modify Processing to use the newly installed version instead of its own. First, copy Processing’s fonts to the newly installed version of Java. You’ll have to change the command lines to reflect the directory structure for your particular installation of Processing. Oracle Java 7 directories should be the same.
cd /usr/lib/jvm/java-7-oracle/jre
sudo cp -R '/home/ignotus_mago/Developer/processing-2.2.1/java/lib/fonts' lib
Next, in your Processing directory, rename the java folder.
cd '/home/ignotus_mago/Developer/processing-2.2.1'
mv java java_old
Now create a symbolic link (symlink) to Oracle 7 Java’s java binary:
ln -s /usr/lib/jvm/java-7-oracle/jre java
At this point, you should be able to run Processing from the Terminal with ./processing. It works for me. YMMV, but I suspect that it should work in most cases.



source

Tags: arduino, processing, ubuntu, data visualization

             

Just point this small device at the TV and the remote gets jammed . The circuit is self explanatory . 555 is wired as an astable multivibrator for a frequency of nearly 38 kHz. This is the frequency at which most of the modern TVs receive the IR beam . The transistor acts as a current source supplying roughly 25mA to the infra red LEDs. To increase the range of the circuit simply decrease the value of the 180 ohm resistor to not less than 100 ohm.

It is required to adjust the 10K potentiometer while pointing the device at your TV to block the IR rays from the remote. This can be done by trial and error until the remote no longer responds

This article is about interfacing a hex key pad to 8051 microcontroller. A clear knowledge on interfacing hex key pad to 8051 is very essential while designing embedded system projects which requires character or numeric input or both. For example projects like digital code lock, numeric calculator etc. Before going to the interfacing in detail, let’s have a look at the hex keypad.
Hex keypad.

Hex key pad is essentially a collection of 16 keys arranged in the form of a 4×4 matrix. Hex key pad usually have keys representing numerics 0 to 9 and characters A to F. The simplified diagram of a typical hex key pad is shown in the figure below.


Hex keypad

The hex keypad has 8 communication lines namely R1, R2, R3, R4, C1, C2, C3 and C4. R1 to R4 represents the four rows and C1 to C4 represents the four columns. When a particular key is pressed the corresponding row and column to which the terminals of the key are connected gets shorted. For example if key 1 is pressed row R1 and column C1 gets shorted and so on. The program identifies which key is pressed by a method known as column scanning. In this method a particular row is kept low (other rows are kept high) and the columns are checked for low. If a particular column is found low then that means that the key connected between that column and the corresponding row (the row that is kept low) is been pressed. For example if row R1 is initially kept low and column C1 is found low during scanning, that means key 1 is pressed.
Interfacing hex keypad to 8051.

The circuit diagram for demonstrating interfacing hex keypad to 8051 is shown below.Like previous 8051 projects, AT89S51 is the microcontroller used here. The circuit will display the character/numeric pressed on a seven segment LED display. The circuit is very simple and it uses only two ports of the microcontroller, one for the hex keypad and the other for the seven segment LED display.


Interfacing hex keypad to 8051

The hex keypad is interfaced to port 1 and seven segment LED display is interfaced to port 0 of the microcontroller. Resistors R1 to R8 limits the current through the corresponding segments of the LED display. Capacitors C1, C2 and crystal X1 completes the clock circuitry for the microcontroller. Capacitor C3, resistor R9 and push button switch S1 forms a debouncing reset mechanism.
Program.
ORG 00H
MOV DPTR,#LUT // moves starting address of LUT to DPTR
MOV A,#11111111B // loads A with all 1's
MOV P0,#00000000B // initializes P0 as output port

BACK:MOV P1,#11111111B // loads P1 with all 1's
CLR P1.0 // makes row 1 low
JB P1.4,NEXT1 // checks whether column 1 is low and jumps to NEXT1 if not low
MOV A,#0D // loads a with 0D if column is low (that means key 1 is pressed)
ACALL DISPLAY // calls DISPLAY subroutine
NEXT1:JB P1.5,NEXT2 // checks whether column 2 is low and so on...
MOV A,#1D
ACALL DISPLAY
NEXT2:JB P1.6,NEXT3
MOV A,#2D
ACALL DISPLAY
NEXT3:JB P1.7,NEXT4
MOV A,#3D
ACALL DISPLAY
NEXT4:SETB P1.0
CLR P1.1
JB P1.4,NEXT5
MOV A,#4D
ACALL DISPLAY
NEXT5:JB P1.5,NEXT6
MOV A,#5D
ACALL DISPLAY
NEXT6:JB P1.6,NEXT7
MOV A,#6D
ACALL DISPLAY
NEXT7:JB P1.7,NEXT8
MOV A,#7D
ACALL DISPLAY
NEXT8:SETB P1.1
CLR P1.2
JB P1.4,NEXT9
MOV A,#8D
ACALL DISPLAY
NEXT9:JB P1.5,NEXT10
MOV A,#9D
ACALL DISPLAY
NEXT10:JB P1.6,NEXT11
MOV A,#10D
ACALL DISPLAY
NEXT11:JB P1.7,NEXT12
MOV A,#11D
ACALL DISPLAY
NEXT12:SETB P1.2
CLR P1.3
JB P1.4,NEXT13
MOV A,#12D
ACALL DISPLAY
NEXT13:JB P1.5,NEXT14
MOV A,#13D
ACALL DISPLAY
NEXT14:JB P1.6,NEXT15
MOV A,#14D
ACALL DISPLAY
NEXT15:JB P1.7,BACK
MOV A,#15D
ACALL DISPLAY
LJMP BACK

DISPLAY:MOVC A,@A+DPTR // gets digit drive pattern for the current key from LUT
MOV P0,A // puts corresponding digit drive pattern into P0
RET

LUT: DB 01100000B // Look up table starts here
DB 11011010B
DB 11110010B
DB 11101110B
DB 01100110B
DB 10110110B
DB 10111110B
DB 00111110B
DB 11100000B
DB 11111110B
DB 11110110B
DB 10011100B
DB 10011110B
DB 11111100B
DB 10001110B
DB 01111010B
END
About the program.

Firstly the program initializes port 0 as an output port by writing all 0′s to it and port 1 as an input port by writing all 1′s to it. Then the program makes row 1 low by clearing P1.0 and scans the columns one by one for low using JB instruction.If column C1 is found low, that means 1 is pressed and accumulator is loaded by zero and DISPLAY subroutine is called. The display subroutine adds the content in A with the starting address of LUT stored in DPTR and loads A with the data to which the resultant address points (using instruction MOVC A,@A+DPTR). The present data in A will be the digit drive pattern for the current key press and this pattern is put to Port 0 for display. This way the program scans for each key one by one and puts it on the display if it is found to be pressed.
Notes.
The 5V DC power supply must be well regulated and filtered.
Column scanning is not the only method to identify the key press. You can use row scanning also. In row scanning a particular column is kept low (other columns are kept high) and the rows are tested for low using a suitable branching instruction. If a particular row is observed low then that means that the key connected between that row and the corresponding column (the column that is kept low) is been pressed. For example if column C1 is initially kept low and row R1 is observed low during scanning, that means key 1 is pressed.
A membrane type hex keypad was used during the testing. Push button switch type and dome switch type will also work. I haven’t checked other types.
The display used was a common cathode seven segment LED display with type number ELK5613A. This is just for information and any general purpose common cathode 7 segment LED display will work here.