How to create a generic Oracle/SQL error messages in .NET

Hello:

I have a bunch of .NET applications on the intranet website. I need to create a generic error message when there is an error occurs due to Security concerns . How to create a generic for Oracle/SQL error message? Instead of showing ORA-01017: invalid username/password; Or ORA-12154: TNS:could not resolve the connect identifier specified...etc...It should say contact the webmaster for assistance. 

I tried to use the same approach below but did not seem to work for Oracle/SQL error msg.  Please help.  Thank you.

<configuration><system.web><customErrors defaultRedirect="GenericError.htm"
                  mode="RemoteOnly"><error statusCode="500"
             redirect="InternalError.htm"/></customErrors></system.web></configuration>