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Protection and security
- 2. members OPULOT PHILIP.A NANTEGE BRIDGET NJAWEZI EZEKIEL NYUMBI SHARRIFU MBADHI BARNABAS OMOIT ANDREW
- 3. Protection Definitions • Protection: It refers to a mechanisim for controling the access of programs, processes, or users to the resouces defined by an Operating system. it involves guarding a user's data and programs against interference by other authorized users of the system.
- 4. Why we need protection -to prevent mischievous -to prevent intential violation of an access restriction by a user -to ensure that each program component active in a system uses system resources only in ways consistent with stated polices
- 5. Advantages of protection. - It allows safe sharing of a common logical address space or common physical address space. Considering the logical address space, if there is a directory of files that has to be shared among multiple users, the protection techniques help to accomplish safe sharing. Considering the physical address space, multiple users can have access to the memory. - it also provides fair and reliable resource usage.
- 6. Goals of Protection Operating system consists of a collection of objects (hardware or software). Each object has a unique name and can be accessed through a well-defined set of operations. Protection problem – to ensure that each object is accessed correctly and only by those processes that are allowed to do so.
- 7. FACETS TO PROTECTION OF INFORMATION There are two facets to protection of information: - SECRECY; it implise that only authorised users should be able to access information - PRIVACY; implises that informtion should be used only for the purpose(s) for which it is intended and shared :- Operating sytems focus on guaranteeing secrecy of information and leaves the issuse of privacy to the users and their processes.
- 8. Security Definitions Security: It refers to providing protection to computer system resouces such as CPU(Central Processing Unit), memory, Disk, software programs it involves guarding a user's data and programs against interference by external entities. eg unauthorized persons.
- 9. Security Attributes Security is defined by three attributes: confidentiality, integrity, and availability. Confidentiality is the prevention of unauthorized modification of information and resources. Integrity is the prevention of unauthorized users. Availability is the prevention of unauthorized withholding of information or resources.
- 10. Reasons for taking security measures - To prevent loss of data - To prevent corruption of data - To prevent compromise of data - To prevent theft of data - To prevent sabotage
- 11. Security Threats The external threats can be of two types as direct threats and indirect threats. A direct threat is an attack on the system from a hacker or a disgruntled insider. An indirect threat is a random attack such as a computer virus, worm, Trojan horse, etc.
- 12. Intruders Intruders and viruses are the two most publicized security threats. We identify three classes of intruders: A masquerador is an unauthorized individual (an outsider) who penetrates a system to exploit legitimate users’ accounts. A misfeasor is a legitimate user (an insider) who accesses resources to which they are not privileged, or who abuses such privilege. A clandestine user is an individual (an insider or an outsider) who seizes control of a system to evade auditing controls, or to suppress audit collection.
- 13. Malicious Software(program threats) The most sophisticated threats to computer systems are through malicious software, sometimes called malware. Malware attempts to cause damage to, or consume the resources of, a target system. Malware can be divided into programs that can operate independently, and those that need a host program; and also into programs that can replicate themselves, and those that cannot. A trap door is a secret entry point into a program, often left by the program’s developers, or sometimes delivered via a software update. A logic bomb is code embedded in a program that ”explodes” when certain conditions are met, e.g. a certain date or the presence of certain files or users. Logic bombs also often originate with the developers of the software. A Trojan horse is a useful (or apparently useful) program that contains hidden code to perform some unwanted or harmful function.
- 14. A virus is a program that can ”infect” other programs by modification, as well as causing local damage. Such modification includes a copy of the virus, which can then spread further to other programs. A worm is an independent program that spreads via network connections, typically using either email, remote execution, or remote login to deliver or execute a copy of itself to or on another system, as well as causing local damage. A zombie is an independent program that secretly takes over a system and uses that system to launch attacks on other systems, thus concealing the original instigator. Such attacks often involve further replication of the zombie itself. Zombies are often used in denial-of-service attacks.
- 15. Authenitcation Goal of authentication: Reasonable assurance that anyone who attempts to access a system or a network is a legitmate user Three mechanisms include;- -Password(patterns or pin) - Physical token or an artifact eg. Swipe cards -Biometric measures eg.finger prints,facerecogintion etc
- 16. Assets and their Vulnerabilities I.Hardware is mainly vulnerable to interruption, either by theft or by vandalism. Physical security measures are used to prevent these attacks. II.Software is also vulnerable to interruption, as it is very easy to delete. Backups are used to limit the damage caused by deletion. Modification or fabrication through alteration (e.g. by viruses) is a major problem, as it can be hard to spot quickly. Software is also vulnerable to interception through unauthorized copying: this problem is still largely unsolved.
- 17. III.Data is vulnerable in many ways. Interruption can occur through the simple destruction of data files. Interception can occur through unauthorized reading of data files, or more perniciously through unauthorized analysis and aggregation of data. Modification and fabrication are also obvious problems with potentially huge consequences.
- 18. III.Data is vulnerable in many ways. Interruption can occur through the simple destruction of data files. Interception can occur through unauthorized reading of data files, or more perniciously through unauthorized analysis and aggregation of data. Modification and fabrication are also obvious problems with potentially huge consequences. IV.Communications are vulnerable to all types of threats. Passive attacks take the form of eaves dropping, and fall into two categories: reading the contents of a message, or more subtly, analyzing patterns of traffic to infer the nature of even secure messages. Passive attacks are hard to detect, so the emphasis is usually on prevention. Active attacks involve modification of a data stream, or creation of a false data stream. One entity may masquerade as another (presumably one with more or different privileges), maybe by capturing and replaying an authentication sequence. Replay is a similar attack, usually on data. Message contents may also be modified, often to induce incorrect behaviour in other users. Denial of service attacks aim to inhibit the normal use of communication facilities. Active attacks are hard to prevent (entirely), so the emphasis is usually on detection and damage control.
- 19. V.Protection Muti-programming involves the sharing of many resources, including processor, memory, I/O devices, programs, and data. Protection of such resources runs along the following spectrum: - No protection may be adequate e.g. if sensitive procedures are run at separate times. - Isolation implies that entities operate separately from each other in the physical sense. - Share all or nothing implies that an object is either totally private or totally public. - Share via access limitation implies that different entities enjoy different levels of access to an object, at the gift of the owner. The Operating System acts as a guard between entities and objects to enforce correct access. - Share via dynamic capabilities extends the former to allow rights to be varied dynamically. - Limit use of an object implies that not only is access to the object controlled, the use to which it may be put also varies across entities. The above spectrum is listed roughly in order of increasing fineness of control for owners, and also increasing difficulty of implementation.
- 20. Computer protection and security mechanisms provided by an operating system must address the following requirements: 1.Confidentiality : (or privacy) the requirement that information maintained by a computer system be accessible only by authorized parties (users and the processes that run as/represent those users). Interception occurs when an unauthorized party gains access to a resource; examples include illicit file copying and the invocation of programs. 2.Integrity: the requirement that a computer system’s resources can be modified only by authorized parties. Modification occurs when an unauthorized party not only gains access to but changes a resource such as data or the execution of a running process. 3.Availability: the requirement that a computer system be accessible at required times by authorized parties. Interruption occurs when an unauthorized party reduces the availability of or to a resource. 4.Authenticity: the requirement that a computer system can verify the identity of a user. Fabrication occurs when an unauthorized party inserts counterfeit data amongst valid data.
- 21. Protection and Security Design Principles Least privilege: Every object (users and their processes) should work within a minimal set of privileges; access rights should be obtained by explicit request, and the default level of access should be “none”. Economy of mechanisms: security mechanisms should be as small and simple as possible, aiding in their verification. This implies that they should be integral to an operating system’s design, and not an afterthought. Acceptability: security mechanisms must at the same time be robust yet non-intrusive. An intrusive mechanism is likely to be counter-productive and avoided by users, if possible. Complete: Mechanisms must be pervasive and access control checked during all operations — including the tasks of backup and maintenance. Open design: An operating system’s security should not remain secret, nor be provided by stealth. Open mechanisms are subject to scrutiny, review, and continued refinement.
- 22. Security and protection: Policies and Mechanisms Security policy -Specify whether a person can become a user of the system. This funtion is performed by the system adimistrator mechanisms Add or delete usersVerify whether a person is an autherised user Protection policy -Specify whether a user can access a specific file. The owner of a file performs this function while creating it mechanisms Set or change protection of informantion for a fileChecks whether a file can be accessed by a user
- 23. Security models. Security models can be discretionary or mandatory - Discretionary Holders of right can be allowed to transfer them at their discretion - Mandatory Only designated roles are allowed to grant right and user connot transfer them
- 24. Consists of three principal componets -A set of passive object,(files, terminals,devices and other entities) -A set of active subjects, which may manipulate the object. -A set of rules governing the manipulation of objects by subjects -Access matrix Model Objects Subjects File 1 File 2 File 3 User 1 r,w r r,w,x User 2 r r r,w,x User 3 r,w,x r,w r,w,x
- 25. - Role Based Acces control - Enforces access controls depending upon a user role(s) -Roles represent specific Organistion duties and are commonly mapped to job titles, for example.Adimistrator, Developer etc
- 26. - Take Grant Model - This model use graphs to model access control - The graph structure can be represented as an adjancency matrix and labels on the arcs can be coded as different values in the matrix., Nodes in the graph are of two types, one crosseponding to subject and other to object. The possible access rights are read(r), write(w), take(t) and grant(g)
- 27. Security policy verses security model - Security policy Outlines several high level points, how the data is accessed, the amount of security requried and what are the steps when these requirement are not met - Security model The mechanism to support the security policy, these involves in the design of the security system
- 28. PROTECTION VERSES SECURITY Protection Security By difintion - a method used in operating systems that manages threats with the system to maintain the proper functioning of the system - a method used in operating systems that handles the threats from outside of the system Main focus - focuses on internal threats of the systems - focuses on external threats to the systems By functionality - provides a mechanism for controlling the access to programs, processes and user resources - provides a mechanism to safe guard the system resources and user resources from external users By mechanism - involves mechanism such as setting or changing protection information of a resource and checking whether that resource is accessible by a user - involves mechanisms such as adding, deleting users, verifying whether a specific user is authorised, using anti-malware software.etc
- 29. END THANK YOU