While opening a MSSQL database by webadmin, it shows all databases in ASP.NET Enterprise manager no matter which database owned by the database user.
Guest user is added to database permissions. Guest user allows database access to logins who do not have associated users inside SQL Server databases.
Login to MSSQL Server using MSSQL Server Management Studio
Right click on database->properties->permissions
Make sure that there is no Guest user or he does not have permissions to database
If Guest user exists, revoke the access of access from user database with script:
-- Specify database name in USE statement
REVOKE CONNECT TO [guest]