Summary by I4ENI
The Piwiki installation on https://analytics.starlink.com has WaF and IP address protections enabled to prevent an attacker from accessing and admin console URLs from the Internet. An attacker should only be able to see the /piwik.php /piwil.js /matomo.php pages. All other pages give an error about the gateway not being found.
I found a WaF bypass that allowed me to access the main interface for the Matomo Piwik installation using the following URL scheme. It tricks the WaF into thinking I'm accessing the allowed piwik.js file, but in reality it is the index.php page.
https://analytics.starlink.com/index%2Ephp/piwik.js
There was also an IP address restriction so even if you bypassed the access to the URL using the above trick, you could not access the interface. By adding the following HTTP header with Starlink owned IP address specified, I could access the login page and other various API URLs used by the software application.
X-Forwarded-For: 192.31.242.112
The impact is that this application is now open to exploring for vulnerabilities in the open source software package that has had numerous CVEs in the past.