Stiltwalker is a system we designed to break the audio version of reCAPTCHA. At LayerOne, the original Stiltwalker was released. However reCAPTCHA updated its system to break Stiltwalker in the hours before our talk/release. Prior to these changes, Stiltwalker was able to achieve an accuracy of 99.1%. This talk will describe a narrative of the events that lead to us choosing to break the audio version of reCAPTCHA, the methods we used to break it, the events surrounding our LayerOne talk and reCAPTCHA's response, and most importantly how we have worked around their response to break reCAPTCHA again after their changes since LayerOne.
DC-949 was founded at some point in 2004, and has slowly amassed members of like minded and passionate hackers. Although group attendance rises and falls, some of the core members are Dr. Adam Nichols, Adrian, C-P, Frank^2, Jeffball, Savant, Sintax Error, and Vyrus. In addition to previously running the oCTF contest at DefCon, and the Barcode Shmarcode contest at Shmoocon, DC-949 members have given talks at numerous conferences including LayerOne, Outerz0ne, Thotcon, and DefCon. They have also released several proof of concept applications including Skynet, TwatFS, and Floodgate.