Confidentiality Policies and Integrity Policies by Stefanie Wilcox

Confidentiality Policies n Prevent the unauthorized disclosure of information n Unauthorized alteration of information n The Bell-LaPadula Model

The Bell-LaPadula Model n Military-style classifications n Security Classifications n Security Clearances TOP SECRETTamara,ThomasPersonnel Files SECRETSally, Samuel Files CONFIDENTIALClaire,ClarenceActivity Log File UNCLASSIFIEDUlaley, UrsulaTelephone List File

The Bell-LaPadula Model n Simple Security Condition: S(subject) can read O(object) if and only if l o <= l s, and S has read access to O. n *-Property: S can write to O if and only if l s <= l o and S has write access to O. n Basic Security Theorem: A system is secure, if all transformations satisfy both.

The Bell-LaPadula Model TOP SECRETTamara,ThomasPersonnel Files SECRETSally, Samuel Files CONFIDENTIALClaire,ClarenceActivity Log File UNCLASSIFIEDUlaley, UrsulaTelephone List File

The Bell LaPadula Model n Principle of Tranquility: Subjects and objects may not change their security levels once they have been instantiated. n Declassification problem n Trusted Entities n Strong Tranquility/Weak Tranquility

Integrity Policies n Commercial and Industrial firms are more concerned with accuracy than disclosure. n Goals: 1) Users will not write their own programs, but will use existing production programs and databases. 2) Programmers will develop and test programs on a nonproduction system: if they need access to actual data, they will be given production data via a special process, but will use it on their development system. 3) A special process must be followed to install a program from the development system onto the production system. 4) The special process in #3 must be controlled and audited. 5) The managers and auditors must have access to both the system state and the system logs that are generated.

Integrity Policies n Principles of Operation: Separation of Duty Separation of Function Auditing

Integrity Policies n Biba(1977)--Integrity Model n Low-Water Mark n Ring Policy n Strict Integrity Policy

HDI n Formal Policy(Corporate) n Informal (ERP software, Payroll)

Bibliography Bishop, Matt. Computer Security: Art and Science Hanover Direct Inc. Corporate Information Systems Use Policy \