These are my methods to check and hunt for XML External Entities. I might be missing a lot of things but as the community believe in "sharing is caring" by @CXVVMVII.
- 1.Convert the content type from "application/json"/"application/x-www-form-urlencoded" to "applcation/xml".
- 2.File Uploads allows for docx/xlcs/pdf/zip , unzip the package and add your evil xml code into the xml files.
- 3.If svg allowed in picture upload , you can inject xml in svgs.
- 4.If the web app offers RSS feeds , add your milicious code into the RSS.
- 5.Fuzz for /soap api , some applications still running soap apis
- 6.If the target web app allows for SSO integration, you can inject your milicious xml code in the SAML request/reponse