Emerging Image Game CAPTCHAs for Resisting Automated and Human-Solver Relay Attacks
Song Gao, Manar Mohamed, Nitesh Saxena, Chengcui Zhang · 2015
CAPTCHAs represent an important pillar in the web security domain. Yet, current CAPTCHAs do not fully meet the web security requirements. Many existing CAPTCHAs can be broken using automated attacks based on image processing and machine learning techniques. Moreover, most existing CAPTCHAs are completely vulnerable to human-solver relay attacks, whereby CAPTCHA challenges are simply outsourced to a remote human solver.