Computer Security – ESORICS 2011

Volume 6879 of the series Lecture Notes in Computer Science pp 150-171

A Systematic Analysis of XSS Sanitization in Web Application Frameworks

  • Joel WeinbergerAffiliated withUniversity of California
  • , Prateek SaxenaAffiliated withUniversity of California
  • , Devdatta AkhaweAffiliated withUniversity of California
  • , Matthew FinifterAffiliated withUniversity of California
  • , Richard ShinAffiliated withUniversity of California
  • , Dawn SongAffiliated withUniversity of California


While most research on XSS defense has focused on techniques for securing existing applications and re-architecting browser mechanisms, sanitization remains the industry-standard defense mechanism. By streamlining and automating XSS sanitization, web application frameworks stand in a good position to stop XSS but have received little research attention. In order to drive research on web frameworks, we systematically study the security of the XSS sanitization abstractions frameworks provide. We develop a novel model of the web browser and characterize the challenges of XSS sanitization. Based on the model, we systematically evaluate the XSS abstractions in 14 major commercially-used web frameworks. We find that frameworks often do not address critical parts of the XSS conundrum. We perform an empirical analysis of 8 large web applications to extract the requirements of sanitization primitives from the perspective of real-world applications. Our study shows that there is a wide gap between the abstractions provided by frameworks and the requirements of applications.