Learn what CAPTCHA is and why it is used when you visit websites. Here, you can also take a look at how easy it is to bypass CAPTCHA to access websites.
While visiting a site to sign up for an account or download something, you may have come across a CAPTCHA. It’s that online test that pops up, asking you to type an answer to a simple math problem, type in the characters presented in a picture, or select matching images.
While these tests can sometimes be annoying for users, they have become crucial in ensuring one’s online security.
However, some hackers and scammers use bots—automated scripts—to access a website and hack it or hijack its information. A CAPTCHA is put in place to check whether the user who visited a website is human or a bot.
With that said, let’s have a look at what CAPTCHA is and why it is used on websites.
What is Exactly is a CAPTCHA?
CAPTCHA stands for “Computer Automated Public Turing Test to Tell Computers and Humans Apart.” It is a test that is presented to any website visitor. The purpose of the test is to try and determine whether the visitor is a human or a bot.
To better understand what it is, a Turing test—named after the British mathematician and computer scientist Alan Turing who pioneered Artificial Intelligence (AI)—is used to try and distinguish whether the responder to a test is human or a computer.
However, during Turing’s time in the 1940s and 1950s, computers were not as advanced today. Now, computers are very sophisticated and, with AI, it has become more challenging to tell a human and computer apart.
Overall, the purpose of a CAPTCHA is to try and keep bots—automated scripts or program snippets—from entering and causing disruption on a website.
Here are some common types of CAPTCHAs:
- A simple text-based CAPTCHA that requires the visitor to type the displayed characters in a text box. Bots can easily pass this type of CAPTCHA.
- A slightly harder CAPTCHA which involves solving a mathematical problem, like adding two numbers. A bot would find it difficult to do this.
- Another type of CAPTCHA is a 3D CAPTCHA with 3D characters that you need to type into the text box.
- Then there are image CAPTACHAs and audio CAPTACHAs which can be quite difficult for humans to solve.
Why Do Websites Use a CAPTCHA?
A CAPTCHA attempts to present questions that only a human could answer. For example, you may be offered a set of pictures and be asked to select only photos that have, say, a boat in them.
This kind of test is easy for a human to solve but may be impossible for a bot. At least, that is what a CAPTCHA is supposed to do—keep bots out.
Of course, not all bots are bad. There are good bots that travel the web and index or catalog websites. However, many bots can be malicious, especially those whose primary purpose is to disrupt operations on websites.
Therefore, it has become necessary for websites to use a CAPTCHA to try and fool or stop automated malicious bots that may try to access their information.
However, AI and Machine Learning (ML) have advanced to such a state that bots can now also be trained to overcome a CAPTCHA.
How Bots Bypass CAPTCHA
There are many ways that bots can bypass CAPTCHAs. Here are some of them:
- Using Automated Methods
Scammers use sophisticated methods like extensions and plugins for browsers or Application Program Interfaces (APIs) to solve or bypass CAPTCHAs.
For example, there is an API called DeCaptcher which can be integrated into your applications. It is a service that uses Optical Character Recognition (OCR) to send you information on how to solve the CAPTCHA.
Some free browser extensions like UnCaptcha and Buster abuse the audio recognition option for the visually impaired to solve CAPTCHAs. This is just a simple look at how scammers can bypass CAPTCHAs.
In addition, you can also use a mobile proxy to bypass CAPTCHAs. A mobile proxy can make it more challenging for websites to detect your actual IP address, preventing them from marking your online activities as suspicious or bot activity.
- Using Humans to Solve CAPTCHAs
Aside from automated methods, there are service providers available who use more affordable human labor to solve CAPTCHAs. This is a very low-cost option that people use to bypass the security meant to protect against the abuse of websites.
Overall, using CAPTCHAs is a safety measure to prevent a website from being harmed by malicious bots or scammers. However, nobody likes CAPTCHAs as they are not that easy for humans to solve at times.
Nevertheless, this has not stopped scammers from using bots, browser extensions, APIs, and low-cost human labor to find ways to subvert or bypass CAPTCHAs. This is why we need to develop more alternatives to prevent cybercriminals from bringing harm to the good the Internet has to offer.