Computer security policy

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A computer security policy defines the goals and elements of an organization's computer systems. The definition can be highly formal or informal. Security policies are enforced by organizational policies or security mechanisms. A technical implementation defines whether a computer system is secure or insecure. These formal policy models can be categorized into the core security principles of Confidentiality, Integrity, and Availability. For example, the Bell-La Padula model is a confidentiality policy model, whereas the Biba model is an integrity policy model. [1]

Contents

Formal description

If a system is regarded as a finite-state automaton with a set of transitions (operations) that change the system's state, then a security policy can be seen as a statement that partitions these states into authorized and unauthorized ones.

Given this simple definition, one can define a secure system as one that starts in an authorized state and will never enter an unauthorized state.

Formal policy models

Confidentiality policy model

Integrity policies model

Hybrid policy model

Policy languages

To represent a concrete policy, especially for automated enforcement of it, a language representation is needed. There exist a lot of application-specific languages that are closely coupled with the security mechanisms that enforce the policy in that application.

Compared with this abstract policy languages, e.g., the Domain Type Enforcement-Language, is independent of the concrete mechanism.

See also

Related Research Articles

Information security Protecting information by mitigating information risks

Information security, sometimes shortened to InfoSec, is the practice of protecting information by mitigating information risks. It is part of information risk management. It typically involves preventing or reducing the probability of unauthorized/inappropriate access to data, or the unlawful use, disclosure, disruption, deletion, corruption, modification, inspection, recording, or devaluation of information. It also involves actions intended to reduce the adverse impacts of such incidents. Protected information may take any form, e.g. electronic or physical, tangible or intangible. Information security's primary focus is the balanced protection of the confidentiality, integrity, and availability of data while maintaining a focus on efficient policy implementation, all without hampering organization productivity. This is largely achieved through a structured risk management process that involves:

In the security engineering subspecialty of computer science, a trusted system is one that is relied upon to a specified extent to enforce a specified security policy. This is equivalent to saying that a trusted system is one whose failure would break a security policy.

In computer systems security, role-based access control (RBAC) or role-based security is an approach to restricting system access to authorized users. It is an approach to implement mandatory access control (MAC) or discretionary access control (DAC).

The Bell–LaPadula Model (BLP) is a state machine model used for enforcing access control in government and military applications. It was developed by David Elliott Bell and Leonard J. LaPadula, subsequent to strong guidance from Roger R. Schell, to formalize the U.S. Department of Defense (DoD) multilevel security (MLS) policy. The model is a formal state transition model of computer security policy that describes a set of access control rules which use security labels on objects and clearances for subjects. Security labels range from the most sensitive, down to the least sensitive.

The Biba Model or Biba Integrity Model developed by Kenneth J. Biba in 1975, is a formal state transition system of computer security policy that describes a set of access control rules designed to ensure data integrity. Data and subjects are grouped into ordered levels of integrity. The model is designed so that subjects may not corrupt data in a level ranked higher than the subject, or be corrupted by data from a lower level than the subject.

In computer security, mandatory access control (MAC) refers to a type of access control by which the operating system or database constrains the ability of a subject or initiator to access or generally perform some sort of operation on an object or target. In the case of operating systems, a subject is usually a process or thread; objects are constructs such as files, directories, TCP/UDP ports, shared memory segments, IO devices, etc. Subjects and objects each have a set of security attributes. Whenever a subject attempts to access an object, an authorization rule enforced by the operating system kernel examines these security attributes and decides whether the access can take place. Any operation by any subject on any object is tested against the set of authorization rules to determine if the operation is allowed. A database management system, in its access control mechanism, can also apply mandatory access control; in this case, the objects are tables, views, procedures, etc.

Multilevel security or multiple levels of security (MLS) is the application of a computer system to process information with incompatible classifications, permit access by users with different security clearances and needs-to-know, and prevent users from obtaining access to information for which they lack authorization. There are two contexts for the use of multilevel security. One is to refer to a system that is adequate to protect itself from subversion and has robust mechanisms to separate information domains, that is, trustworthy. Another context is to refer to an application of a computer that will require the computer to be strong enough to protect itself from subversion and possess adequate mechanisms to separate information domains, that is, a system we must trust. This distinction is important because systems that need to be trusted are not necessarily trustworthy.

Secure by design Software engineering approach

Secure by design, in software engineering, means that software products and capabilities have been designed to be foundationally secure.

The Clark–Wilson integrity model provides a foundation for specifying and analyzing an integrity policy for a computing system.

The Brewer and Nash model was constructed to provide information security access controls that can change dynamically. This security model, also known as the Chinese wall model, was designed to provide controls that mitigate conflict of interest in commercial organizations, and is built upon an information flow model.

The Graham–Denning model is a computer security model that shows how subjects and objects should be securely created and deleted. It also addresses how to assign specific access rights. It is mainly used in access control mechanisms for distributed systems. There are three main parts to the model: A set of subjects, a set of objects, and a set of eight rules. A subject may be a process or a user that makes a request to access a resource. An object is the resource that a user or process wants to access.

A computer security model is a scheme for specifying and enforcing security policies. A security model may be founded upon a formal model of access rights, a model of computation, a model of distributed computing, or no particular theoretical grounding at all. A computer security model is implemented through a computer security policy.

In the fields of physical security and information security, the high-water mark for access control was introduced by Clark Weissmann in 1969. It pre-dates the Bell–LaPadula security model, whose first volume appeared in 1972.

The XTS-400 is a multilevel secure computer operating system. It is multiuser and multitasking that uses multilevel scheduling in processing data and information. It works in networked environments and supports Gigabit Ethernet and both IPv4 and IPv6.

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Trusted Computer System Evaluation Criteria

Trusted Computer System Evaluation Criteria (TCSEC) is a United States Government Department of Defense (DoD) standard that sets basic requirements for assessing the effectiveness of computer security controls built into a computer system. The TCSEC was used to evaluate, classify, and select computer systems being considered for the processing, storage, and retrieval of sensitive or classified information.

Security service is a service, provided by a layer of communicating open systems, which ensures adequate security of the systems or of data transfers as defined by ITU-T X.800 Recommendation.
X.800 and ISO 7498-2 are technically aligned. This model is widely recognized

Cyber crime, or computer crime, refers to any crime that involves a computer and a network. The computer may have been used in the commission of a crime, or it may be the target. Netcrime refers, more precisely, to criminal exploitation of the Internet. Issues surrounding this type of crime have become high-profile, particularly those surrounding hacking, copyright infringement, identity theft, child pornography, and child grooming. There are also problems of privacy when confidential information is lost or intercepted, lawfully or otherwise.

In computer science, language-based security (LBS) is a set of techniques that may be used to strengthen the security of applications on a high level by using the properties of programming languages. LBS is considered to enforce computer security on an application-level, making it possible to prevent vulnerabilities which traditional operating system security is unable to handle.

The Fabric of Security, also known as Cyber Security Fabric or Federated Security, refers to systems designed to protect the Information Systems infrastructure of the home, a corporation or government from malicious attackers. Protection in this sense means guaranteeing the confidentiality, integrity, and the availability of the information stored in the system ("SYSTEM"), and its elements or components.

References

  1. "What is a Security Policy? - Definition from SearchSecurity". SearchSecurity. Retrieved 2022-07-12.