If you read the Windows help pages on Homegroups, you may’ve noticed that Microsoft suggests that you can stop sharing individual files and folders in an otherwise shared library. This is a boldfaced lie. If you use the Share with menu as instructed to unshare a folder in one of your libraries, precisely nothing will happen. Other members will continue to have access to all the files and folders in your shared libraries. The problem with sharing everything is how Windows sets permissions for homegroup shares.
Setting up a Homegroup is easy on this page in Control Panel, but be prepared to dig a bit if it doesn’t work.
For example, Create or join a homegroup, and when prompted, share only your Videos library.
By default, the Videos library sources its files from the My Videos folder, so open Windows Explorer and navigate to My Videos (the folder in \Users\{yourusername}\, not the library). Right-click My Videos, select Properties, and choose the Security tab.
In the Group or user names list, select HomeUsers, and look in the Permissions for HomeUsers box below. You’ll see that the HomeUsers group has read access on this folder. (To learn more about the HomeUsers group, use the Local Users and Groups tool described at the beginning of this chapter.)
Next, choose the Sharing tab. In the Network File and Folder Sharing box, you’ll see that your My Videos folder is currently being shared as \\pc_name \Videos. Then click Advanced Sharing, followed by Permissions, and you’ll see that the Everyone group now has Full Control (Read + Change) over your My Videos folder.
What does this all mean? First, other users who access your shared libraries through the Homegroup folder have read access only, which makes sense. But what Microsoft doesn’t tell you is that sharing a library with your homegroup automatically shares all the folders referenced in your libraries and sets their share permissions to that Everyone has read and write access. As a result, those same users can stroll on over to the Network folder in Windows Explorer, and change your files there.
Now stop sharing the Videos library in your homegroup, or better yet, leave the homegroup entirely. Now, return to the Properties window for your My Videos folder; you’ll see that the HomeUsers group still has read access, and the Everyone group still has read and write access, and the folder is still shared! As far as you know, you’ve unshared this folder, but others on your network can still see and change your files. Now, the lesson is that once you leave the homegroup, you’ll have to remove the lax permissions added to your previously shared folders, and they’ll remain open to snooping.
Even if your PC has no sensitive data on your PC, files in your shared folders are still vulnerable to inadvertent tampering when a family member moves instead of coping a photo, deletes a song accidentally, or makes changes to one of your documents rather than saving to a new file.Read More On How To Secure HomeGroups In Windows?
