Source Code Patterns of Cross Site Scripting in PHP Open Source Projects

  • Felix Schuckert
  • Max Hildner
  • Basel Katt
  • Hanno Langweb


To get a better understanding of Cross Site Scripting vulnerabilities, we investigated 50
randomly selected CVE reports which are related to open source projects. The vulnerable
and patched source code was manually reviewed to find out what kind of source code
patterns were used. Source code pattern categories were found for sources, concatenations,
sinks, HTML context and fixes. Our resulting categories are compared to categories from
CWE. A source code sample which might have led developers to believe that the data was
already sanitized is described in detail. For the different HTML context categories, the
necessary Cross Site Scripting prevention mechanisms are described.