XXe Vulnerability Notes

Reference:
Http://wooyun.jozxing.cc/static/bugs/wooyun-2014-059911.html
Http://bobao.360.cn/learning/detail/3841.html
http://blog.csdn.net/u011721501/article/details/43775691
http://thief.one/2017/06/20/1/
The vulnerability is usually too small, and the impression is that it starts with X, presumably in relation to XML.

Reference: http://thief.one/2017/06/20/1/

XXe vulnerability full name XML External entity injection is an XML external entity injection Vulnerability, XXE vulnerability occurs when an application parses XML input, does not prohibit the loading of external entities, resulting in the loading of malicious external files, resulting in file reads, command execution, intranet port scanning, Attack the intranet site, launch a Dos attack and other hazards. XXe vulnerabilities are often triggered by the location of the XML file can be uploaded, the uploaded XML file is not filtered, resulting in the ability to upload malicious XML files.

However the use of XXe is also dependent on the interpreter.
Reference:
http://blog.csdn.net/u011721501/article/details/43775691
For the same piece of code

<?xml version= "1.0" encoding= "UTF-8"?> <!
DOCTYPE Root [
<! ENTITY% param1 "<! ENTITY internal ' http://www.baidu.com ' > >
%param1;
>
<root>
[This is my site] &internal;
</root>

Safari

Firefox

Chrome

And some of these three browsers will error. XXe bug fix and defense

Filtering user-submitted XML data

Filter Key words: <! DOCTYPE and <! ENTITY, or system and public.

Todo