You have 2 options to BlackList a file, which are by using file name and adding it to the virus database [ using MD5 checksum ]. Please note that file name based BackLists will quarantine your files once detected, where CheckSum based BlackList will follow your preference set for "Action for virus files".
To Balcklist a File using name
Go to cPguard >> Settings >> Scanner :- Into the "Blacklisted Files", add your File Name [ you should add a file name not the complete path ]. This will be active instantly
To Balcklist a File using CheckSum
Go to cPguard >> Settings >> Scanner :- Into "Additional entry to Virus database", specify the path of your file on server and click on Add. This is not instant and need a service restart to fetch the changes.
To whitelist a file
Go to cPGuard >> Settings >> Scanner :- Into the "Whitelisted Files", add your File Name. This will be active instantly. You can add either file name [ it will be applicable for all files with same name ] or complete file path [ specific file ]
cPGuard also supports directory whitelist...please find the details here