Should be able to get a copy through an App Store link
here:https://support.apple.com/en-us/HT208969 Under step 4 - Get macOS
High
Sierrahttps://itunes.apple.com/us/app/macos-high-sierra/id1246284741?ls=1&mt=12
The reason it's reporting as damaged is...
I'm using RHEL 7 server to run our JSS clustered instance in a vCenter
setup. They are all setup with XFS root file systems with the JSS
installed to the default directory (/usr/local/jss). The root FS is only
15GB and that leaves ~6GB free at worst ...
I'm seeing some similar issues, specifically our NetSUS won't find the
10.12.2 update to at least download before we make it available. It also
appears that we are missing the iTunes update entirely.