These credentials are stored in the table tsysconfig.
You can use these fields: [CredWindowsLogin] ,[CredWindowsPassword] ,[CredSNMPPassword] ,[CredSSHLogin] ,[CredSSHPassword] ,[CredVMWareLogin] ,[CredVMWarePassword]
This data is stored in the tabel tsyscredentials. You can only use this table if you use sql server. In the built-in reports we have excluded this table.