public Role

[sukishan]

public Role
  New Information - SQL Server 2000 SP3.

The public role is a special database role to which every database user belongs. The public role:

Captures all default permissions for users in a database.

Cannot have users, groups, or roles assigned to it because they belong to the role by default.

Is contained in every database, including master, msdb, tempdb, model, and all user databases.

Cannot be dropped.
To protect against unauthorized data access, minimize the permissions granted to the public role. Instead, grant permissions to other database roles and to user accounts associated with logins.