CAPTCHA

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.

 

Input Validation Attacks

What are Input Validation Attacks?

Input Validation Attacks :-

Input Validation Attacks are where an attacker intentionally sends unusual input in the hopes of confusing the application.
The most common input validation attacks are as follows-

1) Buffer Overflow :- Buffer overflow attacks are enabled due to sloppy programming or mismanagement of memory by the application developers. Buffer overflow may be classified into stack overflows, format string overflows, heap overflows and integer overflows. It may possible that an overflow may exist in language’s (php, java, etc.) built-in functions.

To execute a buffer overflow attack, you merely dump as much data as possible into an input field. The attack is said to be successful when it returns an application error. Perl is well suited for conducting this type of attack.

Here’s the buffer test, calling on Perl from the command line:
$ echo –e “GET /login.php?user=\
> `perl –e ‘print “a” x 500’`\nHTTP/1.0\n\n” | \
nc –vv website 80

This sends a string of 500 “a” characters for the user value to the login.php file.

Buffer overflow can be tested by sending repeated requests to the application and recording the server’s response.


2) Canonicalization :- These attacks target pages that use template files or otherwise reference alternate files on the web server.

 The basic form of this attack is to move outside of the web document root in order to access system files, i.e., “../../../../../../../../../boot.ini”. This type of functionality is evident from the URL and is not limited to any one programming language or web server. If the application does not limit the types of files that it is supposed to view, then files outside of the web document root are targeted, something like following-

/menu.asp?dimlDisplayer=menu.asp
/webacc?User.asp=login.htt
/SWEditServlet?station_path=Z&publication_id=2043&template=login.tem
/Getfile.asp?/scripts/Client/login.js
/includes/printable.asp?Link=customers/overview.htm


3) Cross-site Scripting (XSS) :- Cross-site scripting attacks place malicious code, usually JavaScript, in locations where other users see it. Target fields in forms can be addresses, bulletin board comments, etc.

We have found that error pages are often subject to XSS attacks. For example, the URL for a normal application error looks like this:
http://website/inc/errors.asp?Error=Invalid%20password
This displays a custom access denied page that says, “Invalid password”. Seeing a string
on the URL reflected in the page contents is a great indicator of an XSS vulnerability. The attack would be created as:
http://website/inc/errors.asp?Error=<script%20src=…
That is, place the script tags on the URL.


4) SQL Injection :- This kind of attack occurs when an attacker uses specially crafted SQL queries as an input, which can open up a database. Online forms such as login prompts, search enquiries, guest books, feedback forms, etc. are specially targeted.

The easiest test for the presence of a SQL injection attack is to append “or+1=1” to the URL and inspect the data returned by the server.
example:- http://www.domain.com/index.asp?querystring=sports’ or 1=1–

Sticky Key Attack Security

Secure your Computer by Sticky Key Attack

Hello Guys,
 This Time I wanna tell you some more about the Sticky keys Attack  i.e. totally about making a backdoor  in other system by replacing sethc.exe file with cmd.exe and after that u have to press Shift key 5 times on login screen and you get the cmd or command Prompt on login screen and run the ‘net user ’ command to change the password  of administrator or any account in the system. This is all about the attack, now how can U Secure ur system by this attack for that you have to follow few steps as follows:


Windows XP:

1. Check for sticky key backdoor “By pressing sticky key  5 times on login screen ”  whenever  you turn on the computer .
2. Turn off the sticky Keys .
3. Or you can use this step to disable the ‘net user’ command, so that if anybody make a backdoor  in your system but he can’t change your password .
   1. Open the folder c:\windows\system32
   2.  Search for ‘Net.exe’ over there and replace it with ‘cmd.exe’ or with any other ‘.exe’ file.
   3. Open the file by inserting this address c:\windows\system32\dllcache on file browser manually and change the ‘net.exe’ with ‘cmd.exe’ or any other ‘.exe’ file.

Windows 7:

1. Check for sticky key backdoor “By pressing sticky key  5 times on login screen ”  whenever  you turn on the computer .
2. Turn off the sticky Keys .
3. Or you can use this step to disable the ‘net user’ command, so that if anybody make a backdoor  in your system but he can’t change your password .
   1. Open the folder c:\windows\system32
   2. Search for ‘Net.exe’ over there and replace it with ‘cmd.exe’ or with any other ‘.exe’ file.
   3. Open the file by inserting this C:\Windows\winsxs\x86_microsoft-windows-net-command-line-tool_31bf3856ad364e35_6.1.7600.16385_none_5208a7a3d3caa54c on file browser manually and change the ‘net.exe’ with ‘cmd.exe’ or any other ‘.exe’ file.
    

Facebook Trick

Hello Guys,

This post of mine is just to make yourself easy with handling your social life. Here I will be telling you various shortcuts for Facebook in Google Chrome & Mozilla Firefox browser.


Chrome        Firefox             Facebook

Alt+m                      Shift+Alt+m               New Message
Alt+0                       Shift+Alt+0                Help Center
Alt+1                       Shift+Alt+1                Home Page
Alt+2                       Shift+Alt+2                Profile Page
Alt+3                       Shift+Alt+3                Manage Friend List
Alt+4                       Shift+Alt+4                Message List
Alt+5                       Shift+Alt+5                Notification Page
Alt+6                       Shift+Alt+6                Account Settings
Alt+7                       Shift+Alt+7                Privacy Settings
Alt+8                       Shift+Alt+8                Facebook Fan Page
Alt+9                       Shift+Alt+9                Facebook Terms
Alt+?                       Shift+Alt+?                  Search Box

Scroogled

Microsft’s New Website: www.scroogled.com (Short form of Screw Google.com)

In a vicious attack on Google, Microsoft has alleged that the company violates the privacy of Gmail users by reading their emails to serve up advertisements.

Microsoft, which competes with Google, has also launched a website – www.scroogled.com – that talks about “Google’s practice of going through the contents of all Gmail emails to sell and target ads”.

Justification by google Said: No humans went through the mails; only algorithms determined the ads.

Stefan Weitz, Microsoft’s senior director of online services, said, “Emails are personal and people feel reading… their emails to sell ads is out of bounds… We are concerned that Google violates privacy every time an Outlook.com user exchanges messages with someone on Gmail.”


Advertising allows co to offer free services: Google
Launching an attack on Google, Stefan Weitz, Microsoft’s senior director of online services, said “This campaign is as much about protecting Outlook.com users from Gmail as it is about making sure Gmail users know what Google’s doing,” he said.

Commenting on Microsoft’s campaign, a Google spokesperson said that advertising allows the company to offer free services. “Advertising keeps Google and many of the websites and services Google offers free of charge… We work hard to make sure that ads are safe, unobtrusive and relevant,” said Samantha Smith, a Google spokesperson.

“No humans read your email or Google Account information in order to show you advertisements or related information. An automated algorithm determines which ads are shown,” added a Google official.

Personalised advertisements have been a part of the web for several years now and are considered industry practice. Websites like Google and Facebook not only track web users when they are logged into their network but also keep an eye on the content they produce through automated processes. In this way, these websites figure out keywords and serve advertisements that users may need.

In fact, Microsoft too shows personalized advertisements across its websites, including on outlook.com. The company also reads emails landing up in an outlook.com mailbox but claims that it is done to filter out spam.
Google had earlier said that its computers also scan the user-generated content to make services more relevant to users. One example of such service is Google Now, a virtual assistant available on Android phones, which can automatically track a shipment for user after scanning the tracking number in emails that courier companies send.

This is not the first time Microsoft has launched a ‘scroogled’ attack on Google. Last year, Microsoft tried to “educate” web users about Google Shopping, a search engine specific for products. Earlier in 2012, the company created a goofy video in which a person called ‘Gmail Man’ was shown reading messages before they got delivered.

Similarly, this is not the first time Google’s practice to keep track of its users is under spotlight. In the past, the company has faced several lawsuits from consumers. Last year, Google paid a fine of over $22 million to the US Federal Trade Commission for ignoring the Do Not Track option enabled by users of Safari web browser.

In the last few years, the competition between Microsoft and Google has intensified. The rise in popularity of Android devices and cloud-based services like Google Docs means Google is now more than a search engine company. While Microsoft has launched direct attack on Google services with campaigns like ‘scroogled’, Google has hit back by refusing to create Gmail or Google Drive apps for Windows 8 and Windows Phone.
Actually There competition screws normal Users like us. So take Care of your Content placed inside Mails.!!

Youtube UPDATED..!!

Check the New looks of YouTube. Its Better!!

Internet search giant Google has unveiled a fresh look for its video sharing website YouTube. According to the official company’s official blog, the new design emphasizes on subscriptions and channels.

Those changes include placing the video at the top of the page, putting it front and center for the viewer, and adding elements such as subscribe, the social action options, and the video information right below the player, CNET reports.

According to the report, Playlists are on the right, and can be browsed while the video is playing. YouTube also introduced a guide that alerts users of new videos in their subscription list.

The subscriptions and guide can be found on other devices beyond the PC, including Android, iPhone, PlayStation 3, and Google TV, the report said.

BILL GATES..!!

Some fun Facts about “THE BILL GATES”

1) Bill Gates is a BORN Genius.
Born on October 28, 1955 to lawyer father and teacher mother in Seattle, Bill Gates got initiated into the computing world right in his childhood.

At the age of 13, while studying at private Lakeside School, Gates discovered his interest in software and started writing his own computer programs.
According to some reports, Bill Gates sold his first computer program at the age of 17, a time-tabling system for his high school for $4,200.


2) Bill Gates is a Hacker
Interestingly, Gates and three other high school students were banned from computer usage by Seattle-based CCC (Computer Center Corporation) after they were caught exploiting its operating system bugs to steal computer time.


3) Extremely Intelligent
According to reports, Bill Gates scored 1590 on his SAT (Scholastic Aptitude Test). The top score for the test then was 1600. He then got enrolled at Harvard College in 1973. Prior to the mid-1990s, SAT score of 1590 corresponded roughly to an IQ of 170


4) He is a college dropout
Few people know that Gates is actually a Harvard university dropout. Gates who scored 1590 on his SAT test out of 1600 got admission in Harvard University in the year 1973, after completing his high school.
At Harvard University, Gates and his high school friend Paul Allen worked on a version of the programming language BASIC for the first microcomputer — MITS Altair. Two years later in 1975, he decided to opt out of college to start Microsoft, what eventually went on to become the world’s largest software company.
5) Bill Gates Graduated in 2007, He is my Batch Mate
However, in 2007 Bill Gates finally got a degree from Harvard, when the university conferred him with an honorary degree. At Harvard, Gates met Steve Ballmer who joined Microsoft in 1980. CEO Ballmer was Microsoft’s 24th employee.
In 1975, Gates started Microsoft with friend Paul Allen from a rented accommodation in Albuquerque, New Mexico. In 1977, Gates and Allen officially registered a partnership, and Micro-soft became Microsoft.


6) Turning Point of Microsoft
The biggest breakthrough came in 1980 when Microsoft won a contract from IBM to provide operating system MS-DOS for IBM’s new personal computers.
Gates had reportedly once told his university teachers that he aims to become a millionaire by the age 30. And he missed the target by just one year. Gates became a billionaire by the age of 31.


7) Growth of Microsoft
In 1986, the year Microsoft went public with the IPO price of $21/share, Gates became a billionaire. Microsoft stock went public at $21 per share, rising to $28 per share by the end of the first trading day. Initial public offering raised roughly $61 million.
In 1992, Forbes declared Gates to be the richest man in America, worth $6.3 bn. In 1995, Gates became richest man in the world, a crown he continues to hold (he has lost the no.1 slot only once in 2008).


8) Bill gates was convicted.
The founder of world’s biggest software company has also been caught on the wrong side of the law. In 1977, Gates was arrested in New Mexico for allegedly jumping a red light and also driving without a license. (The photo on the left is a mug shot of Gates in police custody).


9) Got married on New Year’s Day
Bill Gates married long-time girlfriend Melinda French in Hawaii on January 1st, 1994. They have three children. Gates is an avid reader, and enjoys playing golf and bridge. In wealthiest list for 17 years in a row Software King Bill Gates has figured in the Forbes 400 list of the wealthiest people in the world for 17 years in a row, from 1993 to 2009. For a brief period in 1999, his net worth went past $100 billion, and new term “cent billionaire” was coined.

In 2008, Gates was dethroned as the richest man by America’s investment Moghul by Warren Buffett whose fortune swelled to an estimated $62 billion, up $10 billion from a year ago. The same year Gates was at no. 3 with fortune of $58 billion. At no. 2 was the Mexican telecom tycoon Carlos Slim, with an estimated net worth of $60 billion.

However, the year 2009 returned Gates his numero uno spot in the Forbes’ The World’s billionaires list. With a net worth of $40 billion, Gates regained his position as the world’s wealthiest from investor Warren Buffett. However, the deepening economic crisis eroded Gates fortune too. Gates lost approximately $18 billion in 2008.


10) Rich People Cannot Predict
If you thought all that Bill Gates ever said was profound, you need to read some of his way off the mark predictions. In 2004, Gates predicted that the problem of spam e-mail messages will be gone within two years. And it’s anyone’s guess how true the prediction has turned out to be.
Similarly, in 1981 Gates reportedly said that nobody would ever need more than 640 kilobytes of memory on their personal computer. Here too Gates went way off the mark, with most PCs today offering at least 2GB of memory.

The tech czar had also said that Microsoft “will never make a 32-bit operating system.” However, in 1992, Microsoft released beta of its first 32 bit Windows NT. NT was the first full 32-bit version of Windows.


11) His Mansion is Heaven
Bill Gates lives in 66,000 square feet situated on the edge of lake Washington. The address is 1835 73rd Ave NE, Medina, WA 98039.
The house is famous for its design and the technology it incorporates. Gates reportedly purchased several pieces of land and houses and built this house adjoining all those. Much of the house is built underground into the hill, so the house looks smaller than it actually is.

The house built in the Pacific lodge style has many marvels including the 17-by-60-foot swimming pool has an underwater music system and a floor painted in a fossil motif. Swimmers can dive under a glass wall and emerge outdoors by a terrace.

Then there’s ornate, paneled library with a domed reading room with oculus (light well), fireplace, and two secret pivoting bookcases, one containing a bar.

HATS OFF to his Achievements.