Re: MD5 & bot Question

At 8:49 AM -0400 4/9/07, Robert Cummings wrote:

On Mon, 2007-04-09 at 08:46 -0400, tedd wrote:

At 1:21 AM -0700 4/9/07, Micky Hulse wrote:

Maybe use flash for this... harder to crack? (Of course, Flash will open door to other problems.) Sorry, coming in on this late. Good work Tedd! Very interesting.

M: Tijnema showed how MD5 could be used to identify an image file and crack my arrow captcha. That's really what this thread was about. I finally came up with enough variations to make it impractical. However, this did make me wonder about the images that M$ and others are using for captchas -- like find the kitty in a set of pictures. The MD5 application could be used to identify as many pictures as any spammer would need. So, I think MD5 method, as described in this thread, would work very well to crack those type of captchas.

I doubt Microsoft is using a static image repository for captchas. Cheers, Rob.

I doubt that their image repository infinite. Plus, I envision a method where a bot could: 1. Scan the site, gather the images and key phrase. 2 MD5 the images. 3. Place all the MD5's with the associate key phrase in a dB. 4. Refresh and repeat. With repeated refreshes (not attempts at trying to enter), the key phrases associated with the MD5's will build and the bot will learn. It works like this -- the phrase "find the kitty" or key word "kitty" will always be associated with the picture of the kitty WHEN "kitty" is the solution. All other key phrases/words associated with the kitty picture will eventually "stack out" as just be background noise as data is gathered. As such, a bot could have a foundation at making an intelligent guess. Also, every guess (successful or not) provides even more data to be considered. The more data gathered, the better the guess. Cheers, tedd -- ------- http://sperling.com http://ancientstones.com http://earthstones.com