Introduced protections against XXE attacks

[pixeebot[bot]]

This change updates all instances of XMLInputFactory to prevent them from resolving external entities, which can protect you from arbitrary code execution, sensitive data exfiltration, and probably a bunch more evil things attackers are still discovering.

Without this protection, attackers can cause your XMLInputFactory parser to retrieve sensitive information with attacks like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [ <!ENTITY xxe SYSTEM "file:///etc/passwd"> ]>
<book>
    <title>&xxe;</title>
</book>

Yes, it's pretty insane that this is the default behavior. Our change hardens the factories created with the necessary security features to prevent your parser from resolving external entities.

+ import io.github.pixee.security.XMLInputFactorySecurity;
  ...
- XMLInputFactory xmlInputFactory = XMLInputFactory.newFactory();
+ XMLInputFactory xmlInputFactory = XMLInputFactorySecurity.hardenFactory(XMLInputFactory.newFactory());

You could take our protections one step further by changing our supplied code to prevent the user from supplying a DOCTYPE, which is more aggressive and more secure, but also more likely to affect existing code behavior:

+ import io.github.pixee.security.XMLInputFactorySecurity;
+ import io.github.pixee.security.XMLRestrictions;
  ...
  XMLInputFactory xmlInputFactory = XMLInputFactorySecurity.hardenFactory(XMLInputFactory.newFactory(), XMLRestrictions.DISALLOW_DOCTYPE);

More reading

* [https://cheatsheetseries.owasp.org/cheatsheets/XML_External_Entity_Prevention_Cheat_Sheet.html](https://cheatsheetseries.owasp.org/cheatsheets/XML_External_Entity_Prevention_Cheat_Sheet.html) * [https://owasp.org/www-community/vulnerabilities/XML_External_Entity_(XXE)_Processing](https://owasp.org/www-community/vulnerabilities/XML_External_Entity_(XXE)_Processing) * [https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/XXE%20Injection/README.md](https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/XXE%20Injection/README.md)

I have additional improvements ready for this repo! If you want to see them, leave the comment:

@pixeebot next

... and I will open a new PR right away!

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[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[pixeebot[bot]]

I'm confident in this change, and the CI checks pass, too!

If you see any reason not to merge this, or you have suggestions for improvements, please let me know!

[pixeebot[bot]]

This change may not be a priority right now, so I'll close it. If there was something I could have done better, please let me know!

You can also customize me to make sure I'm working with you in the way you want.