If you are using Windows Forms to connect to WCF, do not cache credentials
Jason Taylor, Prashant Bansode, Carlos Farre, Madhu Sundararajan, Steve Gregersen
If you are using windows forms application to connect directly with WCF service that requires user name authentication, do not cache the user’s credentials. Instead, ask for credentials every time you connect to the service. Do not cache credentials in memory
or in configuration files and do not hard code credentials in your client.