Does Drupal have any security like Dexterity in Plone?
Drupal has a powerful access control to allow users, site builders and developers grant or deny access to content created in it. The basic of access control is the triplet user-group-permission, where you have users associated to roles associated to permissions.

There's a lot of Drupal contributed modules to extend these features. Content Access is a cool module to restrict content to some roles based on it's own type. Domain Access is another control acccess module, a lil more complicated, which handle the access control to affiliate content to "subsites" (domains, subdomains or non-standard ports). So, if you make a little search in the Modules page of drupal.org for "ACL", "access control" or something like, you'll find a lot of resources to bootstrap your web software development.

Keep drupalizing!