How effective is reCAPTCHA for spam protection? ReCAPTCHA & Alternatives

Google’s reCAPTCHA technology has dominated the CAPTCHA market for well over a decade. With over five million websites using it, reCAPTCHA is still the most popular CAPTCHA technology. But how good is it in protecting your websites, APIs, and apps against spam? And are there better reCAPTCHA alternatives? Let’s find out.

What is reCAPTCHA Spam Protection?

ReCAPTCHA is Google’s CAPTCHA service, meant to protect websites from spam and abuse by separating human users from malicious bots, scripts, and algorithms. It does so with risk analysis techniques and, in some cases, with audio or image recognition challenges.

Here’s how reCAPTCHA works:

• Risk analysis: reCAPTCHA uses risk analysis techniques to determine whether a user is a human or a bot. It considers factors such as the user’s IP address, the time of day, and the user’s past behavior on the site.
• Image challenges: In some cases, reCAPTCHA will present the user with an image to solve. These challenges are designed to be easy for humans to solve but difficult for bots.

While reCAPTCHA is effective at stopping basic forms of spam, it may not be enough to stop more advanced bots that perform account takeovers, payment fraud, scraping, and other malicious activities. Therefore, it is recommended to use other spam prevention methods in addition to reCAPTCHA.

How does reCAPTCHA prevent spam?

ReCAPTCHA uses a variety of signals to determine whether a request originates from a human or not. These signals can include an IP address, whether the request comes from a browser that’s logged into a Google account, how long it takes for a request to solve a challenge, et cetera.

This will stop the most basic forms of spam. The problem is that it doesn’t stop the types of automated threats that typically do the most damage, like advanced bots that perform account takeovers, payment fraud, scraping, and worse. Solving a CAPTCHA isn’t usually a big problem for these kinds of bots.

How effective is reCAPTCHA at preventing spam?

There are several studies where scientists, students, and software engineers have succeeded in writing a script that easily bypassed most reCAPTCHA challenges. For example, three researchers from the University of Columbia created a low-cost attack that solved 70.78% of all reCAPTCHA challenges. 

The most sophisticated bots have several ways to bypass a CAPTCHA. They can mimic human behavior so they’re never served a challenge, are sometimes programmed to click the “I’m not a robot” checkbox automatically, use machine learning to solve an image recognition challenge, or use a CAPTCHA farm to recruit a human to solve its CAPTCHA. None of these are particularly hard to implement.

Why is spam protection essential for websites, APIs, and apps?

Spam protection is extremely important for any business because spam is essentially malware. It’s an automated script that tries to damage your business by worsening the quality of your websites, apps, and APIs. Spam is more than just low-quality forum replies or social media posts. It can also mean:

• A script that writes bad reviews or lowers your star ratings.
• A bot that spams your login pages until it manages to hack a user account.
• An algorithm that scrapes content and copies them to a copycat website.
• A large number of bots that slows down your website until it becomes unusable.

5 ReCAPTCHA Spam Protection Alternatives

Having a good solution to stop spam will significantly lower the possibility of the above threats. You cannot rely solely on reCAPTCHA (or on any CAPTCHA technology) to stop the bots that lead to these threats. Here are five reCAPTCHA spam prevention methods worth investigating.

1. DataDome Spam Protection Software

Because spam is always going to be some form of automated threat, the best CAPTCHA alternative is a solution that doesn’t just stop spam, but stops all forms of malicious automated activity. DataDome is a bot protection solution that does exactly that: it detects and blocks bad bots within milliseconds, before they even land on your website, app, or API.

DataDome takes only minutes to install, integrates easily into your existing tech architecture, and processes trillions of signals every day to detect both known and unknown bots. You can allow-list the bots you want to allow (like the Googlebot) and have a dashboard that shows how many bots DataDome stopped over particular time periods. You can test out the software with a free 30-day trial here.

2. Use a Honeypot

A honeypot is a security mechanism that’s attractive to malicious bots but not to real users. It’s usually a form or a field that’s invisible to humans but that bots can find and will try to fill out. Website owners then usually set up a rule to block anything that tries to fill out or access the honeypot.

The difficulty with honeypots is that they only block spam bots that try to fill out fields and forms. Many bots aren’t designed to do this. Some bots simply want to scrape everything in sight or click on your ads. Other bots want to bring down your website with a DDoS attack. Both types of bots (and there are many more examples) are not stopped with a honeypot.

3. Don’t List Emails Publicly

If you’re struggling with email spam, make sure that you don’t have any emails listed publicly. If you do, chances are that a script is automatically collecting those emails and sending spam to them. Use a contact form instead, or give your users the possibility to message you on social media. 

But if you absolutely want to list emails publicly, put those public email addresses as an image on your website, not as text. Humans will still be able to read the image, while bots (at least those without optical character recognition) won’t be able to do so. 

4. Use a Web Application Firewall (WAF)

A WAF is static bot protection software that uses a set of rules and logic to protect your websites and apps from common software vulnerabilities like cross-site scripting, SQL injections, and session hijacking. It mostly relies on IP reputation to understand which requests should be blocked.

That’s where the downside of a WAF lies too: It’s too static for advanced bots. Bots can now easily rotate between high-quality IPs. They can also mimic human behavior to circumvent a WAF’s rules. A WAF is no longer as effective as it used to be.

5. Set Rate Limits

Rate limits prevent DDoS attacks and other malicious automated behavior that are meant to overload your websites, apps, or APIs. They essentially work by limiting the number of requests a single user or IP can make. For example, you can set a rate limit of sixty requests per minute, one a second. If a user tries to go above that, their request will either be throttled or rejected.

Rate limiting is effective for spam that tries to flood your website, but many advanced bots can either rotate between their IPs (so it’s hard to figure out how many requests a single user has made), or they don’t need that many requests to do significant damage, like with low-and-slow DDoS attacks.

Key Takeaway for Spam Protection

Spam is malware and has no place on your websites, apps, or APIs. While some spam can be blocked with reCAPTCHA, the most effective solution is bot protection software that will catch both spam and other types of automated threats. DataDome blocks known and unknown bad bots within milliseconds. Schedule a live demo today to see how it works.

ReCAPTCHA Spam Protection FAQs

Does reCAPTCHA prevent spam?

ReCAPTCHA is effective in blocking the most basic forms of spam, but will not block the most dangerous types of spam and other automated bots. For that, you need bot protection software that’s specifically geared towards stopping all types of bad bots. DataDome is that software.

What is protected by reCAPTCHA?

ReCAPTCHA blocks the most basic forms of spam; the bots that cannot automatically tick the “I am not a robot” checkbox or cannot solve reCAPTCHA’s image recognition challenges. This is useful in some scenarios, but if you want full protection against the most dangerous types of automated threats, you need to look into reCAPTCHA alternatives.

How do I turn off Google reCAPTCHA?

As a website owner, you can simply decide not to install Google reCAPTCHA to avoid it being an issue for your users. Many reCAPTCHA alternatives offer better spam protection for customer experience that users aren’t frustrated by. As a user, you cannot turn off reCAPTCHA. Regardless of the browser you use, if a website uses reCAPTCHA technology, you’ll occasionally have to solve a CAPTCHA challenge.