Database connectivity issue in SSIS
You can't access the password in the connection string. It's a security measure, regardless of your package protection level.



If you need to use an existing connection, then you need to follow the examples laid out in Todd McDermid's post Use Connections Properly in an SSIS Script Task or in Matt Masson's Accessing OLEDB Connection Managers in a Script

Personal note, I never managed to get Matt's version working but since he was the PM on the SSIS team, I'll assume it's my failed implementation and not his. 

An alternative for accessing the password, since this is tagged with 2008, is to use Configuration. Whether it be XML or SQL Server, store the connection string in an external repository and assign the value to an SSIS Variable. Then, apply an Expression to the Connection Manager's ConnectionString property. Within your script task, you'll be able to access the complete connection string which contains the password.