ColdFusion 2018 Update 12 permission issues on file server access

We updated Coldfusion 2018 from Update 11 to 12 on windows servers and began having permissions issues when trying to read from or write to folders on file servers. ColdFusion can do this for folders on the ColdFusion server but if it is a file server (aka not on the same server), it has issues. Prior to the upgrade the we could perform folder and file related access activities without issue.

We tested this issue with a script which looped over a list of folder paths and performed:

1. Check to see if the folder exists (directoryExists(...))
2. If not create the directory (<cfdirectory action="create"...>)
3. If does exist then just print that it exists
4. Do a directory listing of the folder and dump results to screen (<cfdirectory action="list" ...>)
5. Copy a file from a local server folder to the destination folder (<cffile action="copy" ...>)

We verified that the ColdFusion service account had read and write permissions to all of the folders involved and were even able to use a non-upgraded ColdFusion instance to write to the destination folder with the account.

We tested with the following types of folders:

• Multiple folders on two different file server on our network
• Folders on the same server as the ColdFusion instance

The only folder where the actions worked properly were the folders on the same server as the ColdFusion isntance. For all of the other folders:

1. directoryExists could not find the directory (even though they all exist)
2. It could not create the directory 
3. It provided an empty list of directory contents 
4. It was unable to copy the file over because of access denied 

Once we uninstalled update 12, we performed the same set of tests on the same set of folders (without changing any permissions on the folders) and the script successfully perform all actions on all folders. The issue seems to be related to the update 12. 

We are curious if others have encountered similar issues.