I had a fun project months back, Where I had to deal with digital signal processing and low level audio processing. I was never interested in DSP and all other control system stuffs, But when question arises about breaking things, every thing becomes interesting :) . In this post i'm going to share one technique to fully/ partially bypass reCaptcha test. This is not actually a vulnerability but its better if we call it "Abuse of functionality".
more here......http://www.debasish.in/2014/04/attacking-audio-recaptcha-using-googles.html
more here......http://www.debasish.in/2014/04/attacking-audio-recaptcha-using-googles.html