Slashdot Mirror
Campaign To Kill CAPTCHA Kicks Off
Bismillah writes "CAPTCHA may be popular with webmasters and others running different sites, but it's a source of annoyance to blind and partially sighted people — and dyslexic people and older ones — who often end up being locked out of important websites as they can't read wonky, obfuscated letters any more than spambots can. A campaign in Australia has started to rid sites of CAPTCHA to improve accessibility for everyone."
Makes it useful.
If the campaign was taken over by bots?
"W3C has suggested other techniques such as logic puzzles, limited-use accounts and non-interactive checks to prevent abuse such as fraudulent account creation and spamming."
Its going to be far harder to make an AI that can create a decent logic puzzle as well as make it accessible and hard for computers to solve than it it to make an image and warp it a bit. I think any such puzzle will probably be worse than the audio captcha button.
Yes it is stupid. I understand that spam is a problem, but if you run a website, it's *YOUR* problem. CAPTCHAs make it *MY* problem and that's just stupid.
Make it time prohibitive?
Prevent "5ns form posting" with a cooloff time, and also cache submitted forms from an IP address to prevent duplicates.
You can also implement a 50 message per day limit, and reduce as needed to stop spammers.
If taking a couple seconds to answer a CAPTCHA is too much effort, I probably don't really care what you have to say in the comment section.
I understand that spam is a problem, but if you run a website, it's *YOUR* problem. CAPTCHAs make it *MY* problem and that's just stupid.
If the website you use is overrun by spam to the point of being unusable, then it's your problem as well.
How can we continue to believe in a just universe and freedom to eat crackers if we have no ale?
As someone that runs a website, without CAPTCHAs I'd be fucked.
There are bots that can automatically register on a site, then check the email account for the activation link, in order to start spamming, so that's not a solution.
The newer 'flash games' e.g. 'out of 5 objects, put the drinks in the cooler' are an interesting solution, but that probably still won't work for people with accessibility issues.
Moderation can work on sites like slashdot, but on lower traffic sites not so much, and the signal to noise ratio will be awful.
If Australia pass this and actually clamp down on 'offenders' it will do more harm than good as the only recourse webmasters will have is to not allow people to register/interact with the site as the cost of cleaning up spam will be too high.
The problem with slashdot is that most of its users were bullied and stuffed into lockers as kids!
Offloading some of the responsibility to you as a human co-processor is an effective tactic called Share The Pain. It's not stupid, it's genius. You just don't favor the end result. You can always vote with your mouse and go to another website.
"Love heals scars love left." -- Henry Rollins
there isnt a single thing that everyone will like or approve of.
let's say you change it do you have to answer a simple addition math problem. what you get is someone crying, "i have to answer 5+8?! but i dunno maths you insensitive clod!"
you know that person really exists.
Yes they do. The solution is that they learn simple math so they're a fully functioning member of society. I suggest an intensive period of schooling - say 11-13 years. Oh wait...
Who are you going to cater for next? The guy that can't read the damn form. "But I'm illiterate you insensitive clod"? It's not a question of eliminating all objections, just ones that actually stump your audience. Capture is the worst of the worst. You can have a PhD. and get it wrong a substantial portion of the time.
Mission Accomplished.
If taking a couple seconds to answer a CAPTCHA is too much effort, I probably don't really care what you have to say in the comment section.
Or a couple of minutes considering most capchas are illegible.
I'm a good cook. I'm a fantastic eater. - Steven Brust
Tell that to my 46-y.o. eyes that can barely decipher these increasingly difficult eye puzzles, and I have a computer engineering degree. Think about others, will you?
Steve Magruder, Metro Foodist
What if I want my users to be able to post the form more than 50 times per day?
Cooldowns and cacheing just wont do it. The only real alternative I see is to hide the form behind a login, which in the end is more inconvenient for the end user than a user friendly captcha.
There are simple ones that are easy on the eye out there ( like slashdot's ), and you can make your own quite easily as well. There is one widely used one, reCAPTCHA I think, that is just awful and should be avoided.
It is possible to train an algorithm to recognize CAPTCHA, even if the success rate isn't 100%, it is high enough to enable bots to register on websites with CAPTCHA. So, Australia is only pushing people to find out better solutions than CAPTCHA. In short term, a large amount of spammers will rely on optical recognition algorithms to decipher CAPTCHA anyway.
Achille Talon
Hop!
from automated submissions?
If you don't know any alternatives, you shouldn't be administering them.
Yeah, I guess the folks at Google, Yahoo, Microsoft, Amazon etc don't know what they are doing either. Captcha is used because there is no real alternative if you want anonymous form submissions on your site. There are certain measures we can put in place, in certain contexts, but no catch all one size solution.
Well they did give an alternative...
"According to Hollier, a better way for everyone would be the use of emails to activate and verify users, instead of CAPTCHA"
Yea, suppose I could have clarified by adding "alternatives that aren't worse than what they're replacing," but I figured that was a given.
An enigma, wrapped in a riddle, shrouded in bacon and cheese
Add some fields which start out as regular text fields but then hide them with Javascript. You can give them labels or default values like "Don't change this" in case someone doesn't have Javascript enabled. Give the real fields in your form random names. For the hidden fields, give them names like "subject" or "comments" or "url" (don't use common names for personal info like "email", "fname" etc that the browser might automatically fill out). When they submit the form, check for values in those hidden fields (either any value at all, or a value different than the default). If they are filled out, reject the form. Hiding the fields with Javascript will work for virtually everyone and it doesn't require real people to do anything extra. This will fail against bots that bother to actually render the page or bots that specifically target your site (which can be remedied if you randomize all field names and store the random names in the session to match them up when the form gets submitted), but those are far less common than bots that just get the HTML and parse it to look for form actions and field names.
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black
Yes it is stupid. I understand that spam is a problem, but if you run a website, it's *YOUR* problem. CAPTCHAs make it *MY* problem and that's just stupid.
You assume the website needs you more than you need it. For the standard commercial "wall of ads with some random content between" site, sure, what you say holds true
For a lot of smaller interest-group-themed sites, usually run by a handful of non-IT-gurus, put bluntly you need them more than they need you, and they don't have a full-time body around to read through all new posts to purge the spam.
Now, personally, I prefer the "math word problem" style CAPTCHAs - Because not only do they not discriminate against the blind or the old, they effectively keep out the spam and the stupid. Win-win!
Care to elaborate?
I was about to tell you to take advantage of the audio alternative offered by many services, then I went and tried a reCAPTCHA audio test to make sure I knew what I was talking about.
I apologise for even considering telling you to use those.
If taking a couple seconds to answer a CAPTCHA is too much effort, I probably don't really care what you have to say in the comment section.
Or a couple of minutes considering most capchas are illegible.
This!
More and more, captchas take two or three attempts.
(Disclaimer: IMHO, I'm not senile, dyslexic, a horrible typist. blind. Your opinion may vary).
I suspect some sites are intentionally forcing a fail once or twice, at least occasionally, especially when you enter the word
in a timely interval. Bots probably give up after two failures, and they probably answer quickly.
So implementers make it more and more restrictive and throw in bogus failures.
Sig Battery depleted. Reverting to safe mode.
i've been using minteye on my site. it's a visual captcha, works pretty well. you move a slider back and forth to unscramble an image.
I've been developing websites over 10 years and have never needed a captcha system.
This is how I always go about it:
1) Include a form input element labelled as something common, like a telephone number but on a registration form that would never actually require a telephone number. Hide the parent div using CSS in an external CSS file. When the form is submit, check to see if the element is filled out. If it is, simply display a message that you think their registration may be automated and to try again. If it continues, please contact us by other means (phone, email, etc) and we will help them through it.
2) Time the registration from the time the page is loaded to the time it is submit, if its less than 10 seconds, do the same as above, simply display a message saying you think their registration is automated and to try again, etc.
When used in conjunction I feel I've cut out 99.9999% of spam or false registrations. The timing method has to be done server side and stored in a session, and is fairly involved so not easy to do properly if you are new to web development. There is also the issue of someone hitting the back button to try again after a failed submission (if you don't use client-side validation), and them submitting from a cached page, but can be worked around if you know what you are doing.
Obviously its not bullet proof, and if the CSS file doesn't load then someone would see the extra form element. But its a small price to pay for effective protection.
Anyone else have other methods they use?
It is possible to train an algorithm to recognize CAPTCHA, even if the success rate isn't 100%, it is high enough to enable bots to register on websites with CAPTCHA. So, Australia is only pushing people to find out better solutions than CAPTCHA. In short term, a large amount of spammers will rely on optical recognition algorithms to decipher CAPTCHA anyway.
True, but I think the OPs point is those smart bots are not that frequently encountered. We know it can be beat, but in everyday life it is still not common to encounter such bots, and even when you do, you end up blocking 98% of the bots.
As those bots become more common, captcha will become less and less useful. Its a self solving problem that probably doesn't need any help from government, because government will invariably impose something more stupid and useless.
Sig Battery depleted. Reverting to safe mode.
CAPTCHA will be around as long as it is the best way to stop programatic submissions.
It's well documented that there are several groups who have put put porn sites using collections of images from around the net; then they attack sites that require answering CAPTCHA. When challenged by the CAPTCHA, the forward it on to someone seeking the "free porn", and then forward that persons answer back to the site they are attacking.
So the CAPTCHA-using site wants a human to solve the CAPTCHA, a human solves the CAPTCHA, gets their porn, while the attacker gets into the "protected" web site that they actually wanted to attack.
In the limit, they don't work; in practice, there's an amount of effort barrier that makes your site "sorta safe" from bots, if it's small enough that it's not going to be useful to an attacker as a link farm anyway, since it doesn't have enough page-rank credibility of its own that it's worth subverting.
I'd be curious about what "technical measures" you are talking about. There are some "universal IDs" that help to filter out some of the spam, but it still can slip through in a way that Captchas help prevent. There is also something philosophically wrong with trusting in some huge 3rd party vendor like Facebook, Microsoft, or Google to be processing authentication on your website, not to mention concerns about the NSA tracking everybody who is logging into your website as well.
Again, I'd be curious about what technical measures you are talking about.
I'm not a fan of CAPTCHAs, but your statement makes no more sense that declaring passwords bad because it is the websites problem, not yours.
Looking forward to not needing to look for the "Long S" character on my keyboard anymore http://blog.ambor.com/2013/07/an-unexpected-risk-of-using-re-captcha.html - I'm always worried that my employer is filtering on words like goatfucker when I mean to write goat(Long-S)ucker.
i've been using minteye on my site. it's a visual captcha, works pretty well. you move a slider back and forth to unscramble an image.
I never heard of it, and upon googling it, their own website wouldn't couldn't get pass my no-script. So right there, a significant and growing number of customers would be turned away.
But, I wonder of that would remain effective, after all, bots already exist to recognize letters in images. (Those bots existed before captcha). So as soon as Minteye becomes popular it will be bot-stormed.
I've also seen the word games, these are fairly unique as well. But I'm not sure they couldn't be attacked as soon as they become popular. It almost seems that obscurity is the best we have these days.
Sig Battery depleted. Reverting to safe mode.
If taking a couple seconds to answer a CAPTCHA is too much effort, I probably don't really care what you have to say in the comment section.
It's not longer just a couple of seconds when one has to hit the reload button a dozen or so times before they get a CAPTCHA that's remotely readable.
And half the sites bit-bucket at least some of the data you've entered just as further punishment. So you have to type that in again.
Show me the captcha before I enter any data please. That alone would confuse half the bots out there. (For a while).
Sig Battery depleted. Reverting to safe mode.
Google et al don't rely on CAPTCHAs exclusively, at least not for important things. Google accounts uses phone verification driven by some very sophisticated analyses of the signup data. You can actually choose to skip the CAPTCHA on Google signup if you like, phone verification is used as a replacement.
Mozilla Persona http://www.persona.org/ is the new best one -- not tied to any corp, but without the usability problems of openid
People seem to forget that the term "CAPTCHA" (Completely Automated Public Turing test to tell Computers and Humans Apart) applies to a much broader set of tests than just those obfuscated text-based things that most of us loathe. Banning CAPTCHAs is a silly notion that would adversely affect every site currently using them, as they become swarmed by spammers. Instead of banning them, they should be asking people to use sane, simple CAPTCHAs.
For instance, on a forum I run for a group in a game, I use a form of CAPTCHA that has people drag words into categories. As an example, if our group name was "Guild X of Y", I might make the categories "Words in our group's name" and "Words not in our group's name", then ask them to categorize the words "Guild", "Elephants", "X", "Tree", "Honor", "Plus", and "Ocean". I have about two dozen sets of categories and words configured, and so far it's had a 100% success rate at stopping spammers from registering. It's also made it easier for people to register, since the number of e-mails and other off-forum messages I've received complaining about the difficulty of the CAPTCHA has dropped to 0 while registrations have actually picked up.
Such a system would obviously not work for Google or someone that large, since a spammer would just train the bot to know all of the answers, but for smaller sites, there are plenty of solutions that work just fine, and I'm sure we can find more systems that are simple for a human but complicated for a computer. No need to make something that's so complicated for a human to solve.
Alternatively, go with xkcd's approach to solving the problem of spam.
The NSA and its friends already track who logs into your website (or at least the IPs that do) so I wouldn't worry about that one too much.
One technical measure that has been floated recently is the idea of using Bitcoin. What you do is provably sacrifice some bitcoins to miner fees, thus creating a kind of anonymous passport. That proof of sacrifice has public keys embedded in it to which you own the private keys, and it was provably expensive to create. So the idea is that you sign up with your passport and then if you misbehave, it can get added to a blacklist kind of like how Spamhaus blacklists IP addresses. Now you can set the cost of abuse to a precise degree. Good users only have to pay once and can use the same passport for years. Abusers find their business models are unprofitable.
Unfortunately the software and protocols for that aren't implemented yet.
You realize that many of the people complaining about captchas are blind, right?
Easily solved with an appropriate ALT tag, something like "A picture of a person holding a frankfurter in her right hand." In fact, can't all CAPTCHAS be fixed by simple use of the appropriate tag? "A picture of the characters E, Q, 3, 6, T and 9".
If what presents itself as only the most barely notable disability in day to day life excludes me from your consideration as thoughtful well spoken adult due to a single special circumstance, I don't care too much about your comments either.
Minteye was very thoroughly broken.
http://translate.google.com/translate?sl=ru&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&eotf=1&u=http%3A%2F%2Fhabrahabr.ru%2Fpost%2F167359%2F&act=url
Essentially, the guy realized that jpeg pictures with distortions should have a completely different size than the undistorted picture. But all pictures delivered by minteye were of identical length. He figured they were padding the files with zeros, and he was right. By counting the number of zeros at the end of the file, the local maxima/minima was the correct file. He wrote a few lines of javascript, and it was broke.
John
Facebook Connect is not a "better" idea.
You can hold down the "B" button for continuous firing.
Agreed, my systems (combined) are hit every 3 seconds by spammers and hackers.
While people may hate Captcha, webmasters do as well, until we have something that works at least as good, it stays, along with my other levels of fighting spam. It's imperfect, troublesome, and a hassle at times, but it's still one of the more effective anti-spam systems out.
And no, I will not let you login from Twitter or Facebook or any other junk, that opens up a whole new host of issues.
Looks like it's a flash-based captcha that applies a simple transformation to an advertisement. So, it forces your users to stare at your ads. It's got a huge flaw -- a human might need to decode each ad once to train a bot to decode every instance of that ad. Minteye will work until the point that it gets even a little popular. It would take a competent programmer with experience in image processing an afternoon to break this.
Bad guys run some pretty high traffic sites that oddly enough, require captchas. Their client bots forward the real site captcha to the bad-guy site, which delivers it to a human who wants access to the bad-guy site and answers it - which answer is passed back to the bot and submitted to the legitimate site in real time. They also compromise legitimate captcha-secured sites for the same method. It's the Mechanical Turk method of defeating CAPTCHA. Machine learning of text recognition is not required.
Help stamp out iliturcy.
I recently started getting hundreds of spam signups a day on my site. So I installed a CAPTCHA to prevent that. I setup a standard image CAPTCHA with a plugin for the CMS. More then 80% of the spam sign ups just walked right through it. Then I changed the type of CAPTCHA to an ASCII art CAPTCHA. I haven't had a spam sign up since. The ASCII art CAPTCHA is also much easier to read then weird image CAPTCHAs.
Instead of a CAPTCHA, show them two posts and indicate if none of them, one of them, or both of them are spam posts. Behind the scenes, one if a post you know for sure is good or not and one you don't know about.
You can use the responses to rate users (how effective is this user at rating posts, based on how well they do identifying spam?) and posts (how likely is this post to be spam based on what users say about it?). Bad users and bad posts get booted from the system.
Defeating a human reading the source code is not the point. The point is to defeat a bot reading the source code. Another solution that was pointed out was to use CSS to target the hidden element's parent and hide that through regular CSS, which would eliminate the Javascript. Now you're talking about a bot that renders the entire page and fills out the form visually, which is not common (if done at all).
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black
Even now I'm not sure if letters need to be entered as shown ie: some letters are upper case, some lower case.
I'm leaning towards it doesn't matter.
These are only first impressions, but it looks ridiculously easy to solve automatically.
First of all the warp angle jumps significantly more before and after the "correct" image than between other images, so a fairly simple block tracking algorithm would have a very good chance of identifying the correct image:
[image]
You don't have to get exactly the right image - one or two either side and you're okay.
Secondly, the warped images are significantly less sharp than the correct image - in a purely mathematical sense, too, which means it'd be simple for a computer to identify the correct image (confirmed with high pass filters and histograms).
But it's actually a lot simpler than that, as plover has posted here.
What you've got there is CAPTCHA through obscurity, nothing more.
systemd is Roko's Basilisk.
Anyone using a widespread bulletin board software will know that despite hard Caiaphas, spammer accounts are registered like crazy.
I include a small set of questions and answers relative to the interests of those who would visit the board. E.g., for Slashdot:
Complete the following sentence:
[randomly select from sentences]
"TFA" is an acronym meaning "The _______ Article". (7 letters)
Another alias for "Anonymous Coward" is "________ Dweller". (8 letters)
--etc--
Prior to instituting this simple questionnaire there are usually hundreds of spammers a day. Afterwards? None.
This is actually trivial to solve, indeed I don't even use the session token as a seed for creating new mappings between the numeric question ID, and the answers. So, a diligent spammer could simply collect all the questions then add the responses to the bot... Only THEN would I escalate to the code I've already written that does the randomized mappings, after first swapping in a new set of questions / answers.
But why?! Why wouldn't I use the MORE secure way right away? Because I'm not a fool. It has to be worth their time to enter an authentication war with me. Let them waste time writing a bot solver first, then immediately have their work become useless. In fact, this has already happened a few times. It's even rarer for spammers to then continue escalation -- they could just migrate to one of the other boards that is not so hostile, and upon which pre-made automated solvers still work. In fact, I have found good success Starting with only a single question. Replace the selection function:
sub random(){ return 4; } # Return truly random number, selected by fair dice roll.
Then I can simply revert to the randomized set of questions to escalate the spammer's coding and deployment cost. Thus, gaining yet another defense at little cost.
Any heterogeneous environment has what's called a "Single Point of Failure". This is why sex exists. Combinatorials are a simple way to get some randomness without all kinds of unexpected outcomes that rampant mutations in an asexual production would first attempt. Bacteria can use other methods because they've abstracted reproduction from defense: transformation, conjugation, etc. So, the uniform use of SSL, is stupid to put it mildly. It could have been like a bacteria, standardized and abstracted extensible protocol for defensive encryption... It's not though, it's a dumb for including a heterogeneous set of transforms dictated by AES standard. I mean, virtual machines exist; You're using one to decode font glyphs, and Unicode BIDI right now, but not for extensible encryption? How daft. Pervasive use of a brand of Captcha is equally retarding.
How foolish you humans are to not even learn the most basic of Life's Lessons. Diversity is a defense. When you use science to analyze natural selection's method of Trial and Error, Observation of results and Preservation of favorable outcomes... I bet you don't even make the correlation that Nature invented Science billions of years before you rediscovered it... I bet you don't even realize that's a universal truth inherent to any self improving cybernetic system, from DNA life compilers to C compilers. Ugh. Humans: Can't live with 'em; Can't teach 'em to survive.
Adding rel="nofollow" to any links provided by your untrusted commenters is a good start. It's a promise that Google and other search engines won't do any indexing or page ranking based on the href in the same tag.
Spammers have a pretty common M.O. They sign up with an account and use their spam link as their "home page". They then pollute the blog. The obvious spam is repeated variations on the same topic, and looks like "brand name products, products brand name, brand products name, ..."
Lately, link spam is done with a flattering but generic message that looks like it came from a non-native speaker: "I thanking you for your keen insight, have you other similar articles online? I would like to know more how you come to know this." An unwary site operator will often mistake the flattery for a conversation, and allow the spammer to remain a user. (The flattery is script-generated, by the way.) Their "home page" is often a dummy "news portal", which is just replaying whatever feeds they can get. The trick is this news portal has lots of links to the sites the SEO is trying to push.
While rel="nofollow" will render their efforts to associate their spam with a legitimate blog completely wasted, there are two negatives. First, unless the spammer knows it's there, they're going to spam you anyway. Second, it takes away your contribution of "linkiness" for your legitimate users' links to Google's pagerank algorithm. You can fix this with extra work like "probationary" and "full" users, but then you're taking on the task of rating your readers, which may be Sisyphean on a site the size of Slashdot.
John
I'm neither and they annoy the hell out of me; and those little "validation games" (dump the fish into the bucket, or whatever) are ridiculous time-wasters. I'm also a web developer, so there's that. CAPTCHAs are for lazy web developers to offload the task of anti-bot protection to the user.
Create some dynamic form elements that only display via Javascript DOM and are required by a backend script. Create a per-IP limitation on registrations per 10 minutes. Require a minimum time between form loading and form submission. Require a cookie to submit the form.
The point is: the more variety of anti-bot systems that exist, the less attractive a target there is for bot makers.
Each time I swear it was an Aztec chant out of the Necronomicon to raise the evil dead. (And I'm only being partial sarcastic when I say that.)
Did you know 80 to 90% of the moderators on slashdot wouldn't recognize a troll even if one dragged them under a bridge.
There's an obvious measure: don't allow untrusted users to provide links at all, and sanitize their data (server side) to mangle any protocol headers from their text, like adding a space before any text matching ://, so the results become http :// , https ://, or mailto ://. No search engine will try to follow those. You are already santitizing your inputs to restrict users from posting bad stuff like javascript, right? This is just one more thing to check.
You could even get cute using javascript in the browser to flag the text in red if they try to type a URL so they might know in advance they will get nowhere.
Then, to reward the faithful, you can have a karma system that permits voted-up users to post valid links (like stackoverflow). Or you can have an admin manually grant them "good user standing". Either way, your spammer is either contributing real value to your site (which is great) or they've gone away (which is great.)
John
Show me the captcha before I enter any data please. That alone would confuse half the bots out there. (For a while).
Show me a simple Calculus problem or Trigonometric identity to solve in regular text, instead of a single word all muced up. It would be easier to solve
wolfram alpha can solve this captcha better than a human can
In fact there are cases of localized brain injuries that make anything dealing with numbers nearly impossible for the person while they are otherwise quite normal.
Show me the captcha before I enter any data please.
Yes! God yes! I've walked away from a few sites that expected me to re-enter a whack of data because the CAPTCHA borfed. Including some where I had intended to spend money.
It always seemed stunningly obvious that you carry over the form contents in situations like this.
Three Squirrels
You cannot stop a social problem with a technological measure.
Maybe you can't stop it but you can often reduce it to more manageable levels.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
I have no mod points so I must say that if everyone had that same reflex you just displayed, of checking ones assumptions when it's trivial to do so, humanity would be conquering the universe at this point.