A Formal Approach to Detecting Security Flaws in Object-Oriented Database Schemas
Toshiyuki Morita, Yasunori Ishihara, Minoru Ito · Institutional Repositories DataBase (IRDB) · 1998
Detecting security flaws is important in order to keep the database secure. A security flaw in object-oriented databases means that a user can infer the result of an unpermitted method only from permitted methods. Although a database management system enforces access control by an authorization, security flaws can occur under the authorization. The main aim of this paper is to discuss the detection problem of security flaws for database schemas. This problem is to decide whether or not, when a schema S, an authorization A, and a term to be verified are given, there exists a database instance of S such that a security flaw on exists with respect to A. This paper shows that the problem is undecidable and proposes a decidable sufficient condition for a given schema to have no security flaw. Furthermore, this paper shows that the sufficient condition is also a necessary one if the given schema is monadic (i.e., every method is unary), and evaluates the time complexity to decide the condition.