Types of security in system. Theory of design for security Os. Security hidden troubles in Linux Os. Security policy 1.Audit module 2.Access control module 3.Role based access control module. Architecture

Least privilege Efficiency Open System Complete coordination Privilege separation Simplicity

Access control mode is simple:Access control lists and mandatory access control lists are not

supported.

Security audit mechanism is insecuritySecurity audit mechanism of the present Linux is insecurity

Super user right is greatIf the password is purloined, the system will be not safe at all.

Enforced by organizational polices or security mechanism.

Security mechanism and access control policy for os security design.

1.Audit module 2.Acess control module 3.Role based access control module.

Invasive technology can attack the Kernel of Linux.

Linux security audit module should be designed and applied independently.

Security audit module for kernel.

Event Collect Parser Alerting

Record

Audit log library

Ability to permit or deny the use of particular resource.

It manages physical ,logical or digital resources. To advance security it adds security access control

and Integrated access control sub module.

Subject: Entity that perform action in system.

Object: Entities representing resources to which access may need to controlled .

Subject access an object must pass through Security, Integrated and Discretionary access control modules.

Subject access corresponding security tag library when it through each access control subsystems.

It base on Bell-La padula(BLP) model. It can operate MAC i.e Mandatory access

control and DAC i.e Discretionary access control.

MAC : os provide ability to subject to access or perform some operations on subject.

When subject sends a request to an object , extract security tag of subject and object from security tag library.

 Security Labels assigned to all objects,contain two pieces of information - a classification and a category.

When a user access a resource Os checks the user's classification and categories and compares them to the properties of the object's security label. If the user's credentials match the MAC security label properties of the object access is allowed.

Examples: SE Linux, by NSA, trusted Solaris

The control of access is based on the discretion (wish) of the owner.

Access to system resources is controlled by the operating system.

Each resource object on a DAC based system has an Access Control List (ACL).,contains a list of users and groups to which the user has permitted access.

For example, User A may provide read-only access on one of her files to User B, read and write access on the same file to User C and full control to any user belonging to Group 1.

Examples: Unix, Linux, Windows access control.

It based on Biba Integrity model, that  describes a set of access control  rules designed to ensure data integrity.

It used to add security tag for subjects and objects.

When subject sends a request to object the Biba integrity model extract integrated attributes of subject and object from security tag library to match.

Model Access Control Owner Security Control Policy

DAC Data Owner ACL.MAC Operating System Security Labels.RBAC Administrator Role/Function Positions.

Subject

System call

Access control model

Security tag library

Audit model

Object

Audit log library

RBAC is access policy determined by system.

Used in applications where multilevel security requirement may exists.

Roles are created for various job function and user are assigned roles based on their qualifications.

Role assignment : A subject can execute a transaction only if the subject has selected or been assigned a role.

Role authorization : A subject's active role must be authorized for the subject. 

Transaction authorization : A subject can execute a transaction only if the transaction is authorized through the subject's role memberships

It uses the role-based access control mechanism to control unauthorised access to patient medical information in KDIS.

permissions are not assigned to users but to the roles, thus providing great flexibility in administration and cost reduction

Principle of least privilege

System administrator

Security administrator

Security audit administrator

Principle of least privilege

System administrator

Security administrator

Security audit administrator

Hence the access control module, audit module and role based access control module improve the operating system security.

The group of this three module can prevent the lost and misses of data to improve stability, processing speed of Os.