Completely Automated Public Turing test to tell Computers and Humans Apart used in form validation to restrict access to humans only

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0
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2answers
63 views

Is CAPTCHA necessary when I use token?

I wonder is it a good idea using captcha when using token on login page? I think it's impossible for robots to mess with login page because token changes on every request. Thanks.
0
votes
2answers
73 views

Contact form without validation

one of our web page is a contact form eg name, email, and a textbox for sending comments. It seems like if we leave all of those text fields blank and click the submit button, it still went through ...
4
votes
4answers
371 views

How strong is visualCaptcha?

I like the user interaction of visualCaptcha, but I'm questioning the amount of protection it gives: Since there are only 5 images (by default), isn't is simply a matter of 1 in 5 to get the right ...
0
votes
1answer
66 views

Does Google hand over captcha IPs to webmasters?

Google gets to know a user's IP when someone enters a captcha even if they are using tor (see http://www.wired.com/2014/12/google-one-click-recaptcha/). So, If I go to a non-google website, such as ...
1
vote
2answers
56 views

Is there any reason to include the remote ip when using reCaptcha?

I am implementing Google's reCaptcha in my app. According to the documentation, my API request must include my secret key and the response, and optionally the user's remote ip. For what reasons would ...
-2
votes
2answers
76 views

I don't use captcha in image upload form am I safe?

I don't use captcha for image upload form because I know that upload box value cannot fill automatically, needs to be filled by user manually. Are there any ways that somebody automatically post huge ...
5
votes
1answer
447 views

How good is Google's “No Captcha reCaptcha”?

Google has released a new form of captcha identification of bots, that asks the user to click a single checkbox. It uses image-based verification only if necessary. Could someone please explain to me ...
-2
votes
1answer
99 views

How can I test my CAPTCHA's (or CAPTCHA-alternative's) effectiveness?

Are there any tools available to test the effectiveness of user Turing tests such as CAPTCHAs or honeypots, without intentionally getting the site targeted by spam bots? Or, do I simply have to ...
1
vote
2answers
200 views

CAPTCHAs: How does simple math in cleartext prove you're human?

I'm intrigued that many sites use seemingly random numbers with a random operator as a security check to validate that you're not a bot. Forgive my ignorance in captcha technology, but what is ...
-1
votes
1answer
106 views

Weird characters from contact page [closed]

We've just recreated a contact form on a HTML webpage. We've implemented Google reCaptcha to prevents bots and spammers from abusing the form. We've received some feedback from our client, saying ...
13
votes
2answers
2k views

Best practice in web application security authentication to avoid bruteforce attack

I want to cover the possible cases of attacking. My application already has captcha and two-factor authentication, but how can I avoid a tiny attack without annoying my users? The possible cases that ...
3
votes
1answer
164 views

A potential CAPTCHA phishing attack against reCAPTCHA?

In reCAPTCHA's API (without plugin), the key part is <iframe src="http://www.google.com/recaptcha/api/noscript?k=your_public_key" height="300" width="500" ...
4
votes
3answers
1k views

AntiForgeryToken versus Captcha

I am having some question regarding captcha and AntiForgeryToken Do I need to use captcha if I am using AntiForgeryToken in an MVC application. Does AntiForgeryToken prevents automated form ...
4
votes
2answers
158 views

Human or Bot: Behind the Scene Checks vs CAPTCHA

I'm working on a web app at the moment where we’re trying to remove any user friction and excess steps from our user creation page. To avoid computer bots completely spamming our app we need to have a ...
1
vote
1answer
489 views

REST API: does securing the first call with a CAPTCHA make sense?

Let's say I have an iOS/Android app which rely on a custom REST API for things such as account management (register, login, password reset, get/set user-related data). There is no good way to ...
0
votes
2answers
98 views

Showing CAPTCHA

I'd like to show a CAPTCHA to prevent brute forcing attempts, but I was thinking of showing it whenever a user fails for an invalid username/password combination after X attempts, regardless of ...
3
votes
2answers
275 views

how to scan a web application that uses Captcha

I have a web application I am doing a security assessment on and it uses captcha for both the login and for certain operations inside the app. The interesting thing is that this particular app ...
8
votes
5answers
2k views

Is it ethical to use ReCAPTCHA to decode house addresses? [closed]

I noticed recently that ReCAPTCHA is using house numbers and street numbers as images for humans to decode. How ethical is it for Google to do this to this? Does it hamper privacy of an ...
2
votes
0answers
81 views

How to make a captcha maker [closed]

I want to make a captcha maker. I am using PIL library of python to generate an image. I would like to know how should the image be (i.e. numbers with weird font style or some mathematical ...
2
votes
4answers
468 views

How to prevent users from downloading information from our search engine?

We have developed a search engine (simple search, no login required) where users can search details in the database (Apache Lucene) by entering their name (et. al.), then clicking the search button. ...
0
votes
1answer
293 views

CAPTCHA Bypassing with Captcha Clipping Attack is Like MiTM between servers, Is that even Possible?

Sorry if this is a very amateur question. I was checking out some article regarding CAPTCHA bypassing. And I though this article seemed interesting ...
6
votes
1answer
359 views

Would using Google reCAPTCHA allow Google to cheat?

Wanting to go a step further into reducing the attacking surface from my "register new user" form I think on using reCAPTCHA (the one Google offers). Having bots sorted out from being able to ...
2
votes
3answers
1k views

Is it possible to change IP after each request

I am developing a web application. I am planning to skip CAPTCHAs for the initial signup by an IP so as to improve user experience. I was wondering if I am inviting any security risks by doing this. ...
3
votes
2answers
171 views

What are the security benefits of reset all fields if captcha was failed?

Most of the sites will empty the password field when you fail the CAPTCHA, and often they reset all the fields as well. Is there any security benefit on doing this?
0
votes
4answers
299 views

How to secure my captcha application?

Hello information security stack exchange! I made a captcha application in PHP. It's certainly not a great idea to do so, but I was bored and I wanted to learn about Bézier curves and Bresenham line ...
2
votes
3answers
195 views

What is a good way of preventing captcha jacking attacks?

Captcha jacking is an attack to bypass a captcha by coercing a human into solving the challenge response. Prof of concept code that uses a proxy can be found here. Is there a good method of ...
3
votes
0answers
296 views

What are the statistics on how often client form submissions fail CAPTCHAs? [closed]

We've got plenty of argument that CAPTCHA can easily be beaten, and that they introduce usability problems to users. People say that because they can be broken, they shouldn't be used. So if you've ...
7
votes
1answer
622 views

Why is it hard to prevent scalpers from using bots to buy up lots of concert tickets?

The New York Times recently has an article that talks about how scalpers are using bots to programmatically buy up lots of concert tickets, making it harder for ordinary fans to buy up tickets. For ...
1
vote
1answer
241 views

CAPTCHA Weakness to Automated Attack

EDIT: This question was dumb, I misread the quote that made me ask it. Sorry. This is more of a follow up question from schroeder's answer to another question. schroeder said that CAPTCHAs are ...
1
vote
5answers
327 views

Should I enforce a password policy on a web site?

For a commercial web site, is it important to impose some restriction on passwords to access the system? Eg. special $char, Upper and lower case, numbers, at least a minimum length... Can a CAPTCHA ...
2
votes
1answer
362 views

Can a Javascript - WebGL proof of work system prevent website spam?

Is it a good idea to come up with a Javascript-based Proof of Work system to reduce spam on forums, and other websites? This idea would be similar to HashCash, but the computation would be based on ...
1
vote
5answers
606 views

Good ways to prevent spammers from registering [duplicate]

Possible Duplicate: Is there a true alternative to using CAPTCHA images? Since everyone hates captchas what are good alternatives? I'm looking to prevent the automated creation of accounts ...
10
votes
12answers
6k views

Is there a true alternative to using CAPTCHA images?

Security is about balancing costs and risks, nothing is impossible to beat, specially not typical CAPTCHA implementations, but they do add something no other system seems to offer. I've been reading ...
23
votes
3answers
2k views

If we know CAPTCHA can be beat, why are we still using them?

If we know CAPTCHA can be beat, why are we still using them? A 35% to 90% success rate like wikipedia is stating means software is better at solving CAPTCHAs then I am.
8
votes
4answers
15k views

Why Do we Need CAPTCHA? In what case we should use it?

In what case we should implement Captcha based security?. How accurate it is and if there exists any alternatives for Captcha based Security.
1
vote
1answer
332 views

Protect database resources from fake data inputs via web forms

Scenario: I'm working on a project that needs to accept large amounts of data (customer data) from its users. So it can be normal to have a user trying to add 10,000 or 100,000 records at a time. In ...
6
votes
5answers
2k views

How does CAPTCHA mitigate DDoS attacks?

This seems like an easy question, but I've failed to find an answer. One of the uses of CAPTCHA is to cope mitigate Denial of Service attacks. Suppose an adversary performs excessive login attempts, ...
3
votes
4answers
2k views

CAPTCHA or email confirmation?

I have read that captcha isn't a perfect solution to protect a website where for example the user can create an account, since there are many people in different countries that practicallty read ...
-4
votes
2answers
1k views

Is it possible to break captcha? [duplicate]

Possible Duplicate: Can a CSRF CAPTCHA be defeated? Is it to possible break captcha? If yes, how? If no, why websites use difficult captcha systems?
2
votes
2answers
152 views

Are these email captchas legitimate?

The last week, I've been getting this kind of emails to addresses that I don't use: Dear Sir, Madam, For security reasons and as part of our ongoing fight against spam, it is our policy not ...
1
vote
1answer
324 views

How reliable/secure is QCaptcha?

QCaptcha is an alternative way to protect a website from bots. It required a drag and drop action like this: Question How reliable is this implementation when compared to others mentioned on ...
3
votes
4answers
1k views

Can a CSRF CAPTCHA be defeated?

One defense that developers use to protect against a CSRF attack is to implement a CAPTCHA in critical steps. A CAPTCHA ensures that a human is at the keyboard approving the activity. But I've ...
5
votes
5answers
655 views

Why re-verify with CAPTCHA on failed form entry?

Is there a reason for sites to ask for another CAPTCHA verification when some other part of the registration form, e.g. the username, was invalid?
8
votes
7answers
732 views

What type of captcha will you recommend?

What type of captcha will you recommend? I am looking mainly at usability, ease of use (development too), relatively secure Usability I find that those captcha with very curly words/numbers are ...
2
votes
5answers
1k views

Anyone using Asirra in production? Are there similar alternatives?

The Asirra project is a Captcha alternative that shows you pictures of kittens and puppies to fend off bots and prove that the end user is a human. Is anyone using Asirra (or something similar) in ...