The problem is that the first time you do vagrant up with cdk that has landrush set up, you will be asked to provide your sudo password so that landrush can be set up (unless you used it elsewhere already).
This is definitely true on Mac, most likely on Linux also. On Windows, I expect that you will probably just be shown the system prompt for agreeing that the process uses admin rights.
When I did this yesterday (while testing cdk 2.2 rc1), I actually started it from terminal first, so I could enter my password in the console. But I'm pretty sure this wouldn't work in Eclipse. So we need to figure out how to handle this scenario and also test what happens on Windows after installing devsuite and then starting cdk from devstudio - that is our most important use case.