Security and privacy

The last link you show is a joomla link (and the two other could be either Wordpress or Joomla links, as Moodle doesn't have a '/groups' subdirectory).

I know for a fact that Wordpress has lots of security issues and you have to keep it up-to-date, regularly installing the latest versions (they don't fix the security problems in previous versions, they tell you to upgrade to the latest version). And many of them have been serious security issues that could be used to infect other software installed in your web site (like Joomla and Moodle in your case).

Joomla is less problematic than Wordpress, but it's had its share of security problems aswell (just like Moodle, no softaware is perfect).

So you should also check your Wordpress and Joomla installas (the core program, and any additional plugins or themes you have installed).

Saludos.
Iñaki