XML External Entity [ XXE ]

https://blog.detectify.com/2014/04/11/how-we-got-read-access-on-googles-production-servers/

http://nerdint.blogspot.com.eg/2016/08/blind-oob-xxe-at-uber-26-domains-hacked.html

https://seanmelia.files.wordpress.com/2016/01/out-of-band-xml-external-entity-injection-via-saml-redacted.pdf

https://httpsonly.blogspot.com.eg/2017/01/0day-writeup-xxe-in-ubercom.html

http://esoln.net/Research/2017/03/30/xxe-in-lithium-community-platform/