Modern cloud environments amplify the impact of out-of-band vulnerabilities by allowing subtle network interactions to cascade across large, distributed systems. Detecting issues such as server-side request forgery, XML external entities, cross-site scripting and remote code execution requires visibility beyond traditional inline testing. Project Dusseldorf addresses this gap by capturing and analyzing network interactions triggered indirectly through DNS and HTTP, then responding dynamically through a rule-driven engine. By externalizing observation and response, teams gain reliable signals for blind vulnerabilities while reducing manual effort and false positives. The approach supports continuous discovery, variant identification and large-scale testing without requiring persistent instrumentation in target systems.

This video lesson, taught by Michael Hendrickx, principal security research manager at Microsoft, will cover:

• Out-of-band techniques for identifying blind application vulnerabilities;
• DNS and HTTP as scalable signals for vulnerability detection;
• Using rule-based responses to validate exploitability.