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Uncaptcha2: Defeat ReCaptcha with Google Speech2Text
- dwighttk 8y agowhy not use the project link? https://github.com/ecthros/uncaptcha2 https://github.com/ecthros/uncaptcha2
- TelmoMenezes 8y agoBecause the twit summarizes the interesting bit, while the project page not so much. Which is good to motivate people to learn more about the project, right?
- fxfan 8y agoTldr: Captcha -> request Audio verification-> download mp3 and send to google API for recognition -> 91% accuracy
- r3bl 8y agoI'm using Buster[0] for this purpose, and it relies on the same method. Available on Firefox, Chrome and Opera in their respective add-on stores, and no additional steps are needed (like in this project). From my experience, it works perfectly in a default session and not at all in the private browsing mode. I've never bothered to figure out why is that (possibly some other add-on interfering). [0] https://github.com/dessant/buster https://github.com/dessant/buster
- zamadatix 8y agoreCAPTCHA relies on things like Google cookies to lower the "user is a bot" risk score. Higher risk scores (such as when you go via a blank slate browsing session) result in more/more difficult challenges.
- darkpuma 8y ago> more difficult challenges. That's just code for "it rejects correct answers to frustrate you." If you manage to get the noscript version of the captcha with otherwise the same browser state it will accept a correct answer the first time nearly every time. Presumably this is because they didn't bother to implement their "hassle the user" code in the noscript version; it's probably neglected by google since it's disabled by default. For instance, the sloooow fade in of challenge tiles... what legitimate purpose does that serve? That's not there to make it harder for bots. That's there just to hassle and punish real humans that google dislikes because they don't buy into the google 'ecosystem'. The more they dislike you, the slower the fade in gets. The fade-in can be several seconds long in severe cases.
- taneq 8y agoI run a combination of uBlock Origin, Privacy Badger and Firefox's tracking protection. Can confirm, tiles take 5 seconds to fade in, I have to do 3-5 rounds of it, and unless it's really important I'll just tell reCaptcha to piss off.
- bennofs 8y agoIf your score is too low, you aren't allowed to do the audio challenge at all
- ltc5505 8y agoThe creator of that repo commented in this thread as well. Pretty neat.
- Y_Y 8y ago> Sorry, you are rate-limited. Please wait a few moments and try again. I don't know why twitter blocks my Android Firefox, but I feel as if we both benefit.
- zufallsheld 8y agoSame problem for me on Android with Firefox.
- sciurus 8y agoWow, so it's not just me! I'll ask around Mozilla and see if anyone knows why Twitter does this.
- r3bl 8y agoA refresh usually helps, and this "feature" isn't exclusive to Firefox. For some reason, it is exclusive to the links opened from another apps and doesn't appear when accessing a link directly (via a refresh). That might narrow down your search a bit.
- berbec 8y agoI always was rate limited until I signed into Twitter. Problem solved. I think they cap guest views/minute.
- paulgb 8y agoIt happens to me too, also on Firefox mobile. I assumed it was because I block some trackers but maybe not? Also t.co links from within the Twitter app don't load at all from me until I hit "open in Firefox" on the drop-down.
- Infinitesimus 8y agoIt happens to me often when I open a reddit link from twitter in an embedded WebView (using the bacon reader app) so it's unlikely to be a mozilla issue
- Memosyne 8y agoI'm guessing Google will start using some sort of steganography to prevent this from happening.
- zamadatix 8y agoHistorically they just make it more complicated http://www.dc949.org/projects/stiltwalker/ http://www.dc949.org/projects/stiltwalker/ Steganography prevents for people to use their exact service while making it more difficult in general prevents people from using any existing service.
- ilovetux 8y agoI think a simpler solution would be to check if a text to speech API request resulted in the correct answer as part of validating a captcha submission.
- desas 8y agoThere are other free text to speech APIs.
- dwd 8y agoYou would think they could apply a hidden track at a certain frequency that is inperceptable to a human or a pattern of changes in volume to prevent it being passed through their API. Of course the next step will be to resample the sound to remove the steganography...and the arms race continues.
- js4ever 8y agoOr simply use other speech to text api not provided by Google
- jdietrich 8y agoThe obvious approach would be to generate adversarial examples. https://blog.openai.com/adversarial-example-research/ https://blog.openai.com/adversarial-example-research/
- tossaccount123 8y agoGoogle doesn't care, they just want free training data. The team behind uncaptcha even gave them 6 months notice and Google still did nothing their own sites are protected by additional measures to detect bots like monitoring mouse movement
- deleted 8y ago[deleted]
- jayd16 8y agoIsn't the text based ReCaptcha pretty ancient at this point? Google's current version is either the simple checkbox (which I assume is checking various things) or the image based version where you have to click on traffic signs. I like to assume that's a live feed from a Waymo car and I'm saving lives.
- anticensor 8y agoObligatory xkcd (crowdsourced steering): https://xkcd.com/1897/ https://xkcd.com/1897/
- darkpuma 8y ago> "Isn't the text based ReCaptcha pretty ancient at this point?" That was v1, they shut it down in March 2018. You won't see it anymore anywhere. > "Google's current version is either the simple checkbox (which I assume is checking various things) or the image based version where you have to click on traffic signs." That's v2. v2 will present you with a simple check box if you're very compliant with the google surveillance system, or will present you will image challenges if you're not (or if it's just in the mood.) v2 is very capricious and will reject correct answers from users google wishes to punish for, e.g. using firefox, using adblockers, using resistfingerprinting, blocking google's cookies, etc. The recently released v3 is the worst of them all; it does away with the image challenges of v2 completely. The user never interacts with it directly, never has an opportunity to persuade v3 that they're a real human by answering any sort of questions. It's nothing more than a measure of how compliant you are with google's surveillance.
- akerro 8y agoI've seen this a week ago on reddit. The researched told google about this vulnerability and Google doesnt care about it, they are totally OK with it. You can see here that captcha doesn't block robots, but blocks people and makes browsing inconvenient. reCaptcha is a way google mines data from us for free.
- nolok 8y agoOh please, what a total joke of a comment. > Google doesnt care about it, they are totally OK with it Google hasn't said they don't care about it, where did you see any of that ? They merely allowed the code to be released despite it still working against the current. Previous experience (namely the original uncaptcha) prove that they intend to find a way to fix it. > You can see here that captcha doesn't block robots, but blocks people and makes browsing inconvenient. Total BS, remember it's not Google that uses it, it's website owners (us), if what you claim was indeed true we wouldn't be using it, we would use something else that did what we wanted. > reCaptcha is a way google mines data from us for free. Of course, through the visual selection it displays when "unsure", although I do not know the detail it seems pretty obvious that once it's sure you're human it sometimes ask you to detect things in picture anyway so as to provide training data (for maps, waymo, image search, whatever ...)
- Boulth 8y ago>> Google doesnt care about it, they are totally OK with it > Google hasn't said they don't care about it, where did you see any of that ? Check this out: > The Recaptcha team is aware of this attack vector, and have confirmed they are okay with us releasing this code, despite its current success rate. Source: https://github.com/ecthros/uncaptcha2/blob/master/README.md https://github.com/ecthros/uncaptcha2/blob/master/README.md
- swsieber 8y agoThe parent addressed that in the next line. > They merely allowed the code to be released despite it still working against the current. Previous experience (namely the original uncaptcha) prove that they intend to find a way to fix it.
- xnx 8y agoCan god make a stone so heavy that he can not lift it?
- deleted 8y ago[deleted]
- akkartik 8y agoFunny story: I can no longer moderate Disqus on my site because it pops up reCaptcha, and I don't even attempt reCaptcha anymore. And I can't ask for support because it pops up reCaptcha. And I can't export my data and delete my account because -- you guessed it -- it pops up reCaptcha. One of these days I'll gird my loins and go into battle to convince a bot that I'm not a bot. One last time.
- dessant 8y agoSometimes it won't accept correct answers either and you're just wasting time training their classifier for minutes. I found the audio challenge to be much faster to get past, so I've started switching to it a couple of months ago, then finally decided to automate it with a browser extension. https://github.com/dessant/buster https://github.com/dessant/buster
- darkpuma 8y agoIf you manage to force google to serve you the noscript version, it tends to accept correct answers the first time with no re-challenges. The javascript version of recaptcha won't let me through no matter how many times I give it correct answers. However websites must specifically allow the noscript version to be used; by default it's disabled for all websites.
- contravariant 8y agoWhat do I have to do to force the noscript version to activate? At this point it's getting impossible for me to pass captchas, and the audio challenge is no help since I just get half a word or some other unintelligible utterance.
- darkpuma 8y agoSometimes disabling javascript using e.g. umatrix can do it, but only in cases where that website operator has elected to use the most permissive setting (this seems to be rare.) 4channel.org is one site that allows noscript captcha, you can try it out there. But I've rarely seen it possible on other sites.
- vowelless 8y agoHere is a similar attempt from 7 years ago (LayerOne 2012). Reveals how 'simple' life was back then. Bonus: the talk is HIGHLY entertaining. Their approach gets counter measured by Google an hour before the talk and so they can’t demo it anymore. https://youtu.be/Mj3thHKeKyg https://youtu.be/Mj3thHKeKyg
- darpa_escapee 8y ago> https://youtu.be/Mj3thHKeKyg https://youtu.be/Mj3thHKeKyg This was entertaining. Thanks for posting it.
- lawrenceyan 8y agoThe importance of recording your demos haha!
- doe88 8y agoIronically sad that this protection is thereby most easily defeated by its purpose of accessibility. Pessimist in me thinks there is no good deed possible in this world.
- robbomacrae 8y agoI used to work at SoundHound and 3 years ago we had some weird illegitimate looking accounts using our Houndify platform.. turns out they were for breaking recaptcha. It was a bittersweet verification that our voice recognition was ahead of Googles but we had to put in protections against that sort of abuse so we weren't enabling spammers...
- aerique 8y agoDid you end up using recaptcha?
- alfongj 8y agoFrom what I can read on the twit and GitHub, the researcher hasn't proven this works at scale. The point of recaptcha is blocking "captcha farms" or automated bots from abusively creating accounts, buying tickets, etc. The author hasn't demonstrated that this attack is effective in those scenarios. The only thing he has shown is a very convoluted way for a human to solve a recaptcha (harder for 99.9% of humans than the standard recaptcha experience) That would explain why Google didn't care about them publishing this.
- bob_theslob646 8y agoVery impressive! Verification seems really hard. How do you go about verifying very other not the user is an actual person?
- kolanos 8y ago1. In OSX, enable VoiceOver (CMD+F5). 2. Navigate to a RECAPTCHA. 3. Click the "I Am not a bot" checkbox. How is this not an exploit? Is Google doing something extra when it detects a screen reader?
- anewguy9000 8y agocaptcha is a lie.
- hartator 8y agoThis exploit has been known for a while. Example: https://github.com/mikeyy/nonoCAPTCHA https://github.com/mikeyy/nonoCAPTCHA
- dang 8y agoUrl changed from https://twitter.com/FGRibreau/status/1080810518493966337 https://twitter.com/FGRibreau/status/1080810518493966337, which points to this.
- timdierks 8y agoThis is irrelevant. Speech-to-text costs $0.006 per invocation (for < 15 seconds) [1], or you can solve 166 captchas for $1. There are already services out there which will solve captchas for $0.50/1000 [2], an order of magnitude cheaper. The fact that Google has a service which will do this inefficiently changes nothing about the threat/cost ecosystem. CAPTCHAs aren't about being a perfect defense, they're about increasing cost to operate at scale. [1] https://cloud.google.com/speech-to-text/pricing https://cloud.google.com/speech-to-text/pricing [2] https://2captcha.com/ https://2captcha.com/, the first hit I found with the search [captcha solving serving price] Disclosure: I work for Google on security and cloud, but not on anything related to captchas or speech to text.
- dessant 8y agoThere are free speech recognition services, such as Wit.ai, and a number of others that have generous free tiers. Also, it's likely that spammers will not bother finding a free public API, and will just use the endpoints of Google Voice Search, or any other similar service from other companies. The unCaptcha paper and the team's research is very much relevant, because it informs the public about the effectiveness of these security systems, and it helps website admins consider these threats and possibly adapt to them.
- kaffee 8y agoI would love to pay money (or do some sort of proof-of-work hashing) rather than solve Google's infuriating, privacy-hostile CAPTCHAs. I rather suspect that Google, as an advertising and consumer-surveillance firm, gets rather a lot of information out of the system.
- edoo 8y ago"The team has allowed us to release the code, despite its current success." First off permission was never needed to release the code. Second, Google's interest in captcha is not to protect websites but to further their machine learning algorithms. Unless the captcha mechanism was destroyed to such an extent nobody used it they will be happy to accept captcha requests from automated systems. Google may seem like it sometimes but it is not your friend.
- mockingbirdy 8y agoI've built the same in the past to solve ReCaptchas and my question is: Why on earth did they publish this? I've kept it secret because Google will close this loophole and probably make it more difficult for disabled people to verify that they're humans. And Google is not dumb: They already know that speech recognition "breaks" their bot detection, just like screen readers - this is about accessibility. Publishing stuff like this will increase the pressure so they will be forced to "improve" their bot detection system - which simply means that even more people won't be able to solve those captchas. Heck, some weeks ago I've tried to solve a ReCaptcha for literally 10 minutes! My answers were right, it was a matter of discrimination. My point is: My bot automation is able to solve a Captcha faster than a human being. This is silly and ineffective. And about the people who've published this: they think they do someone a favor with this. But I can't see how it's in anybody's interest to release this into the public (especially on a site like HN where Googlers are reading). If they would propose a better solution for website owners to secure their sites, fine. But everyone who's talking about "vulnerabilities" like this makes it more difficult for real people to access the websites that they want to use. I know disabled people who can't solve those captchas - it's just too much of a hassle while it's easy for my bot automation to do it. We should really ask ourselves what we're really trying to improve here.