Defeating Captcha

An anonymous reader pointed us at PWNtcha, a package that breaks various on-line captcha algorithms. The site provides numerous examples of easy (Paypal, and an older version of Slashdot make the list) and hard Captcha. It also links various sources explaining why Captcha is a bad idea.

rock paper scissors...

[jpellino]

captcha stops bots
pwntcha breaks captcha
slashdot cremates pwntcha

Heh

[hungrygrue]

Well I'm glad someone is writing code to solve those "prove you aren't a script" images, because a lot of times I can't quite figure them out myself.

• "Q. What is your favorite color?.. No on second thought, nevermind that. What is written in this blob?"
• A. I'm not sure, is this a rorschach test? Oh, I know 4 - 3 - Two flies mating - U - V - Giant Nose - X."

OCR wins

[marked23]

Once all these new algorithms get integrated into OCR software... OCR software might just work.

Re:What Captcha is...

[jd]

A test for humanness will not be convincing until it cuts out 70% of AOL users and 58.2% of Belgium. (58.2% of Belgian users would work, too.)

It would also have to be impossible for lawyers, tax collectors, marketroids and politicians to use. (Taxes are important, I'm just not convinced anyone in the IRS is biologically related to life on this planet.)

As of this time, Captcha fails this test and therefore is quite unsuitable. A better test would be a short quiz on the meaning of that day's Dilbert cartoon.

Re:ADA

[Tumbleweed]

I wonder how captcha complies with the Americans With Disabilities Act

Simple - they just use ALT text for the image! :)

Re:ADA

[TheRaven64]

Hmm. Done right, you could weed out bots and stupid people. Excellent!

Re:Consider the problem

[Anonymous Coward]

I suppose that requires a glut of intelligent posters, but with the entire citizenry of the Internet available, that can't be so hard.

I nearly fell out of my chair laughing. Someone mod this guy +5 funny please.

Is that goatse I see?

[themightythor]

In the table for "Cwazymail", I was trying to figure out what the pictures were. One's an elephant, one's an owl, and one is a man pulling apart his anus. Great!

Re:spammer's low-tech way

[Gordonjcp]

It's very difficult to get around this. Even using things with no text at all, such as the Cwazymail images, you still have this gaping hole that ne'er-do-wells will get in through.

Re:ADA

[Anonymous Coward]

"What is the next logical number in the sequence 1, 3, 5, 7, ...?"

11. Oh, wait, you're not using octal?

Re:rock paper scissors...

[swelke]

Working that backwards: Slashdot cremates pwntcha, un-breaking captcha. Un-breaking captcha un-stops bots. Therefore, slashdot un-stops bots. I was starting to think the whole slashdot system was just an automated method of destroying the internet; now I have proof. Thanks.

Re:Yet another problem hashcash can solve

[xenocide2]

I'm not sure what Hashcash does, but it sounds like I've already got a great idea for a counter-program: Hashcache.

Re:BFD

[SComps]

that would be a draft beer yes?

Re:Goatse Man

[Siva]

But the image is distorted, so while you might be able to determine what it is, your Manager-Bot won't.

Re:Okay, I know I'm going to feel like an idiot, b

[operagost]

I'm from Holland. Isn't that veird?