Hey Atul,
I'm going to close this ticket as it has already been addressed in your private support portal thread. Here was the findings for anyone that is having similar issues:
I verified that hidden projects are exposed in searchs, for example going to Browse > Projects > Search "project name" will return the project's name, community and end date.
In my testing, I found user's can only see the projects listed in the search results, they cannot actually view the project or it's contents. Doing so will return an "unauthorized" error.
This appears to be resolved in Clearspace 2.5.X but is still an issue in Clearspace 2.0.9, I've gone ahead and filed a bug for this: CS-9863. One of our developers will look into this further and resolve it in a future release of Clearspace 2.0.X... let me know if there's anything else I can add to this ticket or if you have any additional questions or concerns.
~Long