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Explore how security researchers discovered and exploited critical vulnerabilities in China's Great Firewall through this 31-minute conference talk from 39C3. Learn about two groundbreaking censorship measurement techniques that evolved from passive experimentation to active attacks against one of the world's most advanced Internet censorship systems. Discover the "Wallbleed" memory disclosure vulnerability found in 2021 that exposed unprecedented internal details of the Great Firewall's operations, including over 2 million leaked HTTP cookies, nearly 27,000 URL parameters containing passwords, SMTP commands revealing email addresses, and evidence of the firewall's internal network traffic. Follow the two-year investigation that collected five billion responses and revealed how real user traffic was being exposed through this security flaw. Understand how researchers tracked the patching process in real-time starting in September 2023, developed "Wallbleed v2" queries to bypass initial fixes, and continued exploiting the vulnerability until March 2024. Examine findings from the anonymous 600GB leak of Geedge Networks source code, packages, and documentation released in September 2024, revealing insights about censorship software development for multiple repressive governments including Pakistan, Myanmar, Kazakhstan, and Ethiopia. Gain technical knowledge about DNS injection systems, memory disclosure attacks, and the intersection between cybersecurity research and digital rights activism in this call to arms for hackers working against Internet censorship.
