Protection and security of operating system
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The document discusses the protection and security mechanisms of operating systems, emphasizing the importance of controlling access to resources to prevent unauthorized use. It explains concepts such as the principle of least privilege, access control models like role-based and capability-based systems, and various security measures to protect against threats. Additionally, it categorizes security violations and highlights the role of the security kernel and user authentication in maintaining system integrity.
Protection and security of operating system
- 1. Group No.5 Name • Muhammad Abdullah • Sarmad Ali • Hashaam Altaf • Hanif Shah • Noman Rasool • Imran Ahmed Roll No. • 02 • 01 • 38 • 45 • 25 • 46
- 2. Topic: Protection and Security of Operating System
- 4. Protection: •Protection refers to a mechanism for controlling the access of programs, processes, or users to the resources defined by a computer system.
- 5. Goals of Protection: •As computer systems have become more sophisticated and pervasive in their applications, the need to protect their integrity has also grown. •We need to provide protection for several reasons. The most obvious is the need to prevent the mischievous, intentional violation of an access restriction by user. • An unprotected resource cannot defend against use (or misuse) by an unauthorized or incompetent user. •The role of protection in a computer system is to provide a mechanism for the enforcement of the policies governing resource use.
- 6. Principles of Protection: •The time-tested guiding principle for protection is the Principle of least privilege. It dictates that programs, users, and even systems be given just enough privileges to perform their tasks. •An operating system following the principle of least privilege implements its features, programs, system calls, and data structures so that failure or compromise of a component does the minimum damage and allows the minimum damage to be done.
- 7. Domain of Protection: •A computer system is a collection of processes and objects. By objects, we mean both hardware objects (such as the CPU, printer) and software objects(such as files, programs). •Each object has a unique name that differentiates it from all other objects in the system, and each can be accessed only through well-defined and meaningful operations.
- 8. Domain Structures. •Each domain defines a set of objects and the types of operations that may be invoked on each object. • The ability to execute an operation on an object is an access right. •A domain can be realized in a variety of ways: •Each user may be a domain. In this case, the set of objects that can be accessed depends on the identity of the user. •Each process may be a domain. In this case, the set of objects that can be accessed depends on the identity of the process.
- 9. Cont… •For example, if domain D has the access right <file F, {read, write}>, then a process executing in domain D can both read and write file F; it cannot, however, perform any other operation on that object.
- 10. Example: UNIX System: •In the UNIX operating system, a domain is associated with the user •In Unix operating system user ID’s use for identify the domain.
- 11. Hashaam Altaf
- 12. Access Matrix: •Our model of protection can be viewed abstractly as a matrix, called an Access Matrix. The column of the access matrix represent domains, and the rows represent objects. Each entry in the matrix consists of a set of access rights.
- 13. Access Control: •Access Control is to control which objects a given program can access, and in what ways. Objects are things like files, sound cards, other programs, the network, your modem etc. •When we talk about ``controlling access,'' we are really talking about four kinds of things: i) Preventing access. ii) Limiting access. iii) Granting access . iv) Revoking access.
- 14. Cont... •A good example of this is found in Solaris 10. •Solaris uses Role-based access control(RBAC) to adding the principle. •Role-based access control (RBAC) is a security feature for controlling user access to tasks that would normally be restricted to the root user. • In conventional UNIX systems, the root user, also referred to as superuser. The root user has the ability to read and write to any file, run all programs, and send kill signals to any process.
- 16. Capability-based Systems: •In a capability-based computer system, all access to objects is done through capabilities, and capabilities provide the only means of accessing objects. In such a system, every program holds a set of capabilities. •If program A holds a capability to talk to program B, then the two programs can grant capabilities to each other. •In most capability-based systems, a program can hold an infinite number of capabilities. Such systems have tended to be slow.
- 17. Cont... •A better design allows each program to hold a fixed (and small -- like 16 or 32) number of capabilities, and provides a means for storing additional capabilities if they are needed. •Here two example are discuss •Cambridge CAP System. •Hydra
- 18. Cambridge CAP System: •The Cambridge CAP computer was the first successful experimental computer that demonstrated the use of security capabilities, both in hardware and software . •The CAP system was designed such that any access to a memory segment or hardware required that the current process held the necessary capabilities. •CAP has two kinds of capabilities. •Data Capability. •Software Capability.
- 19. Cont… •Data Capability: It can be used to provide access to objects, but the only rights provided are the standard read, write, and execute of the individual storage segments associated with the object. •Software Capability: It is a protected procedure, which may be written by an application programmer as part of a subsystem. A particular kind of rights amplification is associated with a protected procedure. When executing the code, a process temporarily acquires the right to read or write the contents of a software capability itself.
- 20. Noman Rasool
- 21. Hydra: •Hydra is a capability-based protection system that provides considerable flexibility. The system implements a fixed set of possible access rights. • In addition, a user can declare other rights. The interpretation of user-defined rights is performed by the user's program, but the system provides access protection for the use of these rights.
- 22. Language Based Protection: •As operating systems have become more complex, and particularly as they have attempted to provide higher-level user interfaces, the goals of protection have become much more refined. The designers of protection systems have drawn heavily on ideas that originated in programming languages and especially on the concepts of abstract data types and objects. •There must be a protection policy to control the access of user defined programs.
- 23. Cont… • Protection systems are now concerned not only with the identity of a resource to which access is attempted but also with the functional nature of that access. •It is usually achieved through an operating-system kernel, which acts as a security agent to inspect and validate each attempt to access a protected resource.
- 24. SECURITY • ensure that each object is accessed correctly and only by those processes of authorized users that are allowed to do so. Security violation of the System can be categorized as: • Breach of Confidentiality: Unauthorized reading of data. • Breach of Integrity: Unauthorized modification of data. • Breach of Availability: Unauthorized destruction of data. • Theft of Service: Unauthorized use of resources. • Denial of service: Preventing legitimate use of the system.
- 25. Imran Ahmed
- 26. Security Measures • Physical: Both the machine rooms and the terminals or workstations that have access to the machines must be secures from physical entry. • Human: Authorization must be done carefully to ensure that only appropriate users have access to the system. • Operating System: The system must protect itself from accidental or purposeful security breaches. • Network: protection from the travel of data to private leased lines like Internet. • User Authentication: User should use some password or biometric authentications to protect the System.
- 27. Security Kernal • Responsible for implementing the security mechanisms of the entire operating system. • Provides the security interfaces among the hardware, the operating system, and the other parts of the computing system. Program Threats: • Virus dropper inserts virus onto the system. Use backdoor to access data. • Trojan Horse: A code segment that misuses its environment is called a Trojan horse. Trap Doors: user’s access privileges code into program. • Virus: A virus is a fragment of code embedded in a legitimate programs. They can wreck havoc in a system by modifying or destroying files and causing system crashes program malfunctions.
- 28. System and Network Threats • System and network threats create situation in which operating system resources and user files are misused. • Worms: A worm is a process that uses the spawn mechanism to duplicate itself. The worm spawns copies of itself using up system resources and perhaps locking out all other processes.