Table of Contents

Even the most groundbreaking technologies need to retire and eventually make way for better solutions. Believe it or not, this is precisely what’s happening with reCAPTCHA today.

That’s not to say that reCAPTCHA didn’t have its time in the spotlight. The CAPTCHA test was first introduced in 1997. It was designed to stop bots from submitting URLs to search engines. CAPTCHA quickly evolved into a method to prevent other types of automated attacks, such as ticket scalping and blog comment spam.

CAPTCHA was invented over 25 years ago. A lot has changed since then, including the intelligence of cyber threats. With the explosive growth of the Internet in the early 2000s, CAPTCHA became a popular way to stop bots from signing up for email accounts and other online services. In 2009, Google acquired reCAPTCHA, which you could describe as a spin-off of the original CAPTCHA we just mentioned.

Although there are over 20 prominent CAPTCHA vendors today, Google’s reCAPTCHA is the most widely used solution. Over 6.3 million websites rely on reCAPTCHA to protect their websites from malicious bots.

But how reliable is reCAPTCHA? Can it really stop bad bots?

Unfortunately, the answer is no. In fact, reCAPTCHA has become increasingly vulnerable to sophisticated bad bots over the years. In this article, we’ll explore why reCAPTCHA can’t stop modern automated attacks. We’ll also take a look at the best reCAPTCHA alternatives that can help you stop bad bots for good.

First, let’s take a closer look at how reCAPTCHA works in the first place.

What is ReCAPTCHA?

ReCAPTCHA is a tool that aims to shield websites from automated attacks. It can stop some bad bots, but not all of them. Sophisticated bots can still get through the CAPTCHA using strategies like automated form filling and IP masking. These bots are designed to mimic human behavior, making it difficult for reCAPTCHA to tell them apart from authentic users.

CAPTCHA vs. reCAPTCHA: What’s the Difference?

A CAPTCHA is a challenge-response test used to ensure that a human is generating the response.

ReCAPTCHA is a specific type of CAPTCHA that includes a risk analysis engine to keep automated software from engaging in abusive activities on your site. It does this by presenting a challenge that is easy for humans to solve but difficult for some bots to figure out.

Types of Threats reCAPTCHA Aims to Prevent

Although many threats traverse the internet, reCAPTCHA is designed to protect against the most common types of automated attacks, such as:

  • Form spam: Automated software that fills out and submits forms on websites. Form spam can be used to collect sensitive information or engage in fraudulent activities like credit card fraud.
  • Ticket scalping: Automated bots that buy up large quantities of tickets for events. These bots sell the tickets at a higher price, making it difficult for people to get affordable tickets.
  • Blog comment spam: Spammy comments that are posted on blog posts to get traffic to a particular website.
  • Brute force attacks: A type of attack where automated software attempts to guess passwords. This can be used to gain access to sensitive information or accounts.
  • Denial of Service (DoS) attacks: When automated software overloads a website with traffic, causing it to crash and become unavailable.
  • Content scraping: When attackers use an automated solution to copy content from websites. This can be used to create duplicate content or steal information.

Despite its best intentions, reCAPTCHA cannot prevent all automated attacks.

reCAPTCHA Kasada


Why is reCAPTCHA Ineffective?

ReCAPTCHA has become increasingly futile when faced with bots that use advanced techniques to bypass the CAPTCHA test.

Here are a few reasons why you cannot continue to rely on reCAPTCHA to protect your website from cyber threats:

Automated Form Filling is Abundant

Bots can automate the process of filling out forms on your website. Without human intervention, they can submit fake sign-ups, spam comments, and other malicious content. Automated form-filling is one of the most common ways bad bots abuse websites.

ReCAPTCHA Does Not Offer Visibility Into Its Impact on Users

You cannot know how many human users are impacted by reCAPTCHA. The tool lacks visibility into its effectiveness in stopping bad bots.

IP Masking Hides Bot Locations

Bots can use proxy servers and VPNs to mask their IP address and make it appear as if they’re coming from a different location. This makes it difficult for reCAPTCHA to determine whether the request comes from a human or a bot.

Bots Leverage Advanced Machine Learning

Bots use advanced machine learning techniques to bypass CAPTCHA tests. These bots can be trained to recognize common CAPTCHA patterns and respond accordingly.

What’s more, bots are becoming more sophisticated every day. As bot developers find new ways to bypass CAPTCHA, Google is constantly playing catch-up, trying to update reCAPTCHA with new tests that are more difficult for bots to solve.

This arms race between bot developers and Google is neverending, and it’s one that you cannot win as a website owner.

ReCAPTCHA Doesn’t Work on All Bots

There are many different types of bots, and not all of them are stopped by reCAPTCHA. For example, chatbots and social media bots are not affected by reCAPTCHA. You’re still vulnerable to specific automated attacks even if you have reCAPTCHA enabled on your website.

ReCAPTCHA is a Target for Cybercriminals

While reCAPTCHA may stop some bots, it’s also a target for cybercriminals. Several cybercriminals have used reCAPTCHA to launch distributed denial of service (DDoS) attacks.

In a DDoS attack, the attacker uses a botnet to flood the target website with requests.  This overloads the server and causes the website to crash.

By setting up a reCAPTCHA on their website, the attacker can use the CAPTCHA test to filter out human users and direct the botnet attacks at the website’s server. This makes it much easier for the attacker to take the website offline.

ReCAPTCHA can also be used to launch phishing attacks. In a phishing attack, the attacker uses a fake website that looks identical to the actual website.  When the user tries to solve the CAPTCHA, they’re actually sending their personal information (like their login credentials) to the attacker.

Cyber Threats Are Constantly Evolving

ReCAPTCHA is ineffective because it needs to keep up with the constantly evolving ways bad bots bypass CAPTCHA tests. ReCAPTCHA lacks long-term efficacy.

As we’ve seen, bots use advanced strategies to bypass CAPTCHA tests. But which ones should you pay the most attention to as you protect your own website?

Let’s look at that next.

The Weapons Sophisticated Bots Use to Conduct Automated Attacks

Now that we’ve covered the techniques bots use for malicious automation, let’s review some of the tools that supplement these methods. Here are some of the most common:

Proxy Networks

Bots can use proxy networks to reroute their traffic and make it harder to identify and block them. This technique is especially effective for botnets, which are networks of infected devices that can be used to carry out DDoS attacks.

Bright Data (formerly Luminati) is a commonly used tool to find and buy proxies. It offers a searchable database that contains millions of proxies, which can be filtered by country, protocol, and other criteria. Proxy networks help bots disguise themselves as legitimate human users by making it appear that their traffic comes from different IP addresses.

Testing Frameworks

Many different testing frameworks are available for bot development, each with its own strengths and weaknesses. Some of the most popular include:

  • Puppeteer: A Node.js library that provides a high-level API to control headless Chrome or Chromium. Attackers often use Puppeteer for web scraping, automating form submission, taking screenshots, and more.
  • Playwright: Another Node.js library to automate Chromium, Firefox, and WebKit with a single API. Malicious actors can use Playwright for the same purposes as Puppeteer.
  • Selenium: A portable framework for testing web applications. Selenium can be used with various programming languages, making it a popular choice for bot development. It supports headless browsers, including Chrome, Firefox, and Safari.

Stealth Plugins

Some bots use plugins to make themselves more difficult to detect. Here are a couple of examples:

  • User-agent switcher: A browser extension that allows the user to change the user agent. This can be used to make the bot appear to be a different type of device, such as a mobile phone or tablet.
  • Proxy rotator: A browser extension that automatically switches between proxies. This makes it harder for defenders to track the bot’s traffic.

Digital Harvesting

Digital harvesting is the process of extracting data from online sources. Of course, attackers can harvest the data manually, but they often automate the process with bots.

Malicious automation allows attackers to gather information at scale, which can be used for a variety of purposes, such as:

  • Creating fake accounts
  • Conducting identity theft
  • Sending spam messages

The most common type of data harvesting is email address harvesting. Cybercriminals use bots to crawl websites and collect any email addresses they find. Then, they sell the data on the black market or use it to spam people.

Phone number harvesting is also a commonly seen threat. Attackers use bots to scrape websites and collect any phone numbers they find.

Attackers can use bots to harvest many other types of data, such as names, addresses, dates of birth, and more. The list is practically endless.

Reverse Engineering

Perhaps the most dangerous type of bot is one that’s been reverse engineered. This is when an attacker takes a legitimate application or website and reverse engineers it to figure out how it works. Once the attacker understands how the application or website works, they can create a bot that mimics its behavior.

Reverse engineering is often used to create bots that bypass CAPTCHAs. Therefore, even if security teams implement solutions that have CAPTCHA-blocking capabilities,  they’re not guaranteed to be effective.

In some cases, attackers will even reverse engineer the CAPTCHA itself to figure out how it works. They can then create a bot that can bypass the specific CAPTCHA by correctly solving the challenge.

Reverse engineering can also be used to create bots that copy human behavior. This is often achieved by observing how a human interacts with an application or website and reproducing those interactions with a bot.

This type of bot is hazardous because it’s challenging to detect. The only way to truly defend against this type of attack is to have a comprehensive security solution that can detect and block malicious traffic.

How Can Bots Bypass reCAPTCHA?

Let’s take a closer look at the process modern bots use to solve CAPTCHAs and bypass reCAPTCHA defenses.

1. An Attacker has a Motivation to Bypass a Company’s Defenses

The first thing to understand is that bad actors have a strong incentive to bypass reCAPTCHA. After all, CAPTCHA-protected forms are designed to stop bots from submitting them.

Bypassing reCAPTCHA allows attackers to automate the process of filling out and submitting forms on your website. This can be used to submit spam comments on blog posts, sign up for email accounts, or even place orders on e-commerce sites.

With a sophisticated bot, cybercriminals can automate many of these processes and scale their attacks to an unprecedented level.

2. CAPTCHA is Presented on the Company’s Website

Using a variety of audio and visual challenges, CAPTCHA asks users to prove they’re “human” before they can proceed.

The most common CAPTCHA challenge is the distorted text test. In this challenge, the user is presented with an image of text that has been distorted in some way. The user must then type the text correctly into a form to bypass the CAPTCHA.

3. Actor makes an API Call to an All-in-One (AIO) Service

To bypass the CAPTCHA, the attacker will make an API call to a service that provides CAPTCHA-solving services, also known as an AIO service.

There are many different CAPTCHA-solving services available online. Some of these services are free, while others charge a fee.

The attacker will send the CAPTCHA image to the service along with some basic information, such as the type of CAPTCHA and the desired text or audio response.

Third-party AIO platforms use a variety of methods to solve CAPTCHAs, including human workers and optical character recognition (OCR) technology.

When attackers request a response from an AIO service, it could be outsourced to:

Human Solvers

A human worker will be presented with the CAPTCHA and asked to enter the correct response. Many of these workers operate within CAPTCHA farms.

A CAPTCHA farm is exactly what it sounds like. It’s a place where large numbers of people are employed to solve CAPTCHAs. These workers are often paid very little, sometimes as little as $0.01 per CAPTCHA.

The use of human workers to solve CAPTCHAs is a scalable solution for attackers. All they need to do is make a request to the AIO service and provide the CAPTCHA image. The service will then take care of the rest.

Auto Solvers

Some AIO services use OCR technology to solve CAPTCHA images automatically. This technology can recognize the text in CAPTCHA images and provide the correct response without human intervention.

Other platforms use a combination of human workers and OCR technology to solve CAPTCHAs. This can provide a more accurate solution and a faster response time.

Audio Solvers

Some CAPTCHA challenges are presented as audio instead of images. In these challenges, the user is asked to listen to a distorted audio clip and then type the correct word or phrase into a form.

Human workers can solve audio challenges, but Google Voice can also help attackers solve these challenges automatically.

4. Bots Mimic Human Behavior to Bypass CAPTCHA

Once the attacker receives an authorized token from the AIO service, they can input the info into the form and bypass the CAPTCHA.

In many cases, the attacker may need to mimic human behavior to avoid detection. This can be done by adding a delay between when the CAPTCHA is presented and when the correct answer is submitted.

The attacker may also use a different IP address for each CAPTCHA attempt. This makes it more difficult for website owners to detect and block the attacker’s activity.

5. As a Result, the CAPTCHA Fails

Attackers can bypass CAPTCHA in many different ways, as we’ve seen. And as CAPTCHA-solving services become more sophisticated, even more effective methods will develop.

CAPTCHA is also an inconvenience for legitimate users. Many users find CAPTCHA challenges to be difficult and time-consuming. This can lead to frustration and abandoned transactions.

Do you really want to rely on a solution that will kill your conversions and still leave you vulnerable to attack?

We didn’t think so. That’s why we’re here to share the most sophisticated reCAPTCHA alternatives available.

What Happens When reCAPTCHA Fails?

Cyberattacks have grave consequences for organizations of all sizes. Let’s take a closer look at what could happen if reCAPTCHA fails to stop a bad bot.

Data Loss

Cybercriminals may steal sensitive information like credit card numbers, login credentials, and trade secrets. This can lead to identity theft, financial loss, and damage to your reputation. Data breaches can also result in heavy fines from regulatory bodies, such as the GDPR.

Service Disruption

Bad bots can launch DDoS attacks, which overwhelm your servers and prevent legitimate users from accessing your website or application. DDoS attacks can severely disrupt your business operations.

Fraudulent Transactions

By bypassing reCAPTCHA and other security measures, cybercriminals can make fraudulent transactions on your website. This can cause a slew of problems, including financial loss, legal trouble, and damage to your reputation.


A bot-induced overload of server requests can result in a DoS attack. This can cause your website or application to crash, leading to lost revenue and frustrated customers.


Bad bots can fill your forms with spammy content, such as fake reviews and links to malicious websites. This can damage your reputation and lead to penalties from search engines. If you rely on organic traffic, a manual penalty from Google can directly impact your revenue.


Attackers can use bots to collect information for phishing attacks. They may submit fake forms with malicious links or scrape your website for customer data. Phishing attacks can lead to data loss, service disruption, and fraudulent transactions.


Bad bots can bypass security measures, such as age verification and location restrictions. They can then commit fraud, such as ticket scalping and fake account creation.

The effects of a bad bot attack can be far-reaching and devastating. That’s why it’s so important to have an effective solution in place to stop them (a.k.a. NOT reCAPTCHA).

So, What is the Most Effective reCAPTCHA Alternative?

Believe it or not, this is a bit of a trick question. Instead of trying to replace reCAPTCHA, we recommend rethinking your bot mitigation strategy completely.

Why? Because attackers take one of two approaches when defeating a CAPTCHA:

  1. They make themselves undetectable, or
  2. They automate the CAPTCHA-solving process.

ReCAPTCHA and similar solutions all run into the same problem. Attackers have found effective workarounds for all of them.

To truly stop bad bots, you need to take a proactive approach that can detect and block them, regardless of how they try to bypass your security measures.

Instead of finding an alternative for reCAPTCHA, you need to replace it with a solution that takes a totally different approach to bot mitigation and detection.

The Best Strategy to Defend Against Malicious Automation

Bad bots come in all shapes and sizes. They can be simple scripts or sophisticated AI-powered software. They can mimic human behavior, or they can be completely automated.

The only way to defend against all bad bots is with a multifaceted approach that can detect and block them, regardless of their type or behavior.

Additionally, you don’t have to kill the customer experience to stop malicious automation. With the right technology, you can stop attacks without losing conversions from frustrated customers who don’t want to waste their time playing I Spy with a CAPTCHA.

What’s the best way to stop bad bots? With a dynamic, data-driven approach that can detect and block them, regardless of how they try to bypass your security measures.

Meet Kasada: The Future of Bot Mitigation

Kasada is a bot mitigation platform that takes a proactive approach to stop malicious automation.

Kasada’s technology is constantly learning and evolving, so it can effectively stop sophisticated AI-powered bad bots that can bypass reCAPTCHA.

Here’s how Kasada’s platform works:

Our Solution Knows All the Tricks

Like we mentioned earlier, bot operators often use DevTools, stealth plugins, solver services, anti-detect browsers, and proxy networks to evade detection. Kasada’s technology can detect and block all of these strategies.

Our solution offers actionable insights that distinguish good bots, bad bots, and humans so you can understand your website traffic and block automated threats. Better yet, our software does not require each user to prove that they are “human” like reCAPTCHA does.

Kasada is CX Approved

Kasada is built with the customer experience in mind. Our platform does not require users to solve CAPTCHAs, answer quizzes, or do any other type of security challenge that could kill conversions.

We Offer Dynamic, Responsive Defenses Against Bots

Static defenses are not enough to stop sophisticated threats. A static defense is a security measure that does not change, regardless of the type or behavior of the attacks it is trying to defend against. For example, a CAPTCHA is a static defense because it does not change, regardless of the type or behavior of the bots trying to bypass it.

Instead of relying on rule-based systems, Kasada adapts to the changing landscape of malicious automation in real-time. Smart bots that try to reverse engineer our defenses will find themselves playing an ever-changing game of Whac-A-Mole that they can never win.

Kasada Stops Attacks Before they Happen

Kasada’s technology stops bad bots in their tracks instead of waiting for them to strike. We do this by analyzing website traffic and identifying malicious behavior in real-time.

When we identify a threat, we automatically block it before it can cause any damage. This way, you don’t have to worry about attackers wreaking havoc on your website or stealing your customers’ data.

Why Choose Kasada?

Kasada is the most effective bot mitigation platform on the market because it helps you identify and block even the most sophisticated automated tools without sacrificing the customer experience.

Stop BotsImprove Security Like Never Before

You can onboard our solution in a matter of minutes, and we offer 24/7 customer support to help you every step of the way.

Our powerful analytics tools give you insights into your website traffic so you can understand the behavior of your users and take action against malicious automation.

Kasada is backed by a team of world-class security researchers who are constantly improving our technology to stay ahead of the latest threats.

Streamline the User Experience

Kasada helps you optimize the user experience and improve conversions by automatically verifying users. Our platform uses a variety of signals to determine whether a user is human or not instead of relying on reCAPTCHA.

Additionally, reducing bot traffic will help you improve service availability, increase site speed, improve mobile responsiveness, and increase conversions.

Maximize ROI

When you eliminate bad bot traffic, you will lower your data center, cloud, and bandwidth costs. You’ll also see a decrease in chargebacks, fraud, and abuse.

You’ll also increase your operational agility by freeing up human resources to tackle threats that require their intelligence. Instead of fighting bots, your team can focus on investigating fraudulent activity and maintaining legacy systems.

Finally, Kasada’s technology is highly efficient and scalable, so you can be sure that your investment will pay off in the long run. Our software gathers insights that you can use to make informed decisions about your security posture.

Kasada is the Most Effective Way to Stop Bad Bots

Our platform has been battle-tested by some of the world’s largest organizations, and we’re constantly improving our technology to stay ahead of the latest threats.

If you’re looking for a proactive, effective, and easy-to-use solution to stop bad bots, Kasada is the right choice for you.

Ready to stop bad bots for good? Request a demo of Kasada today.

Want to learn more?

  • SMS Fraud Takes A Toll: The Evolving Threat of SMS Pumping and Toll Fraud

    After a crack down on SMS fraud, adversaries have shifted their approach.

  • Freebie Bots: The Latest Threat to Retailers

    Steep discounts drove Cyber Monday online sales to hit record highs, but some discounts were created by mistake.

Beat the bots without bothering your customers — see how.