Subdomain takeover on *.apachecn.org

## Summary

The domain **apachecn.org.io** has a subdomain wildcard CNAME record pointing to **apachecn.github.io**. This allows an attacker to use any subdomain he wants on apachecn.org with Github pages.

## Security issue

An attacker could create it's own repository and configure it to use any subdomain he wants, allowing him to serve it's own content.

## POC

I have made [a POC](http://what-i-want.apachecn.org/).


## Remediation

Remove the wildcard CNAME record for apachecn.org.

## Impact

This issue make it possible for an attacker to carry out several type of attacks like XSS, phishing campaign or session hijacking.