CAPTCHAs are widely used to protect websites against malicious robots. Yet, CAPTCHAs are being broken routinely by spammers, malware authors, and other nefarious characters. This talk will review and demonstrate many of the implementation weaknesses that are routinely exploited to break image-based CAPTCHAs, and offer suggestions for improving the effectiveness of CAPTCHAs. Rather than attempt an in-depth examination of any single CAPTCHA or technique, we will present a broad overview of tools with the aim of making it easy for anyone to take a shot at cracking the CAPTCHAs on present and future high-profile sites.