Exercise physical security activity 1 please read the

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Exercise: Physical Security Activity 1: Please read the above article and understand the scenario Activity 2: Do some research on Physical security threats /issues Activity 3: Write your understanding in your own words in one paragraph Activity4: Enlist some security threats related to the physical security you encounter in your daily life Activity 5: Give some recommendations how you can protect with those threats
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Chapter 3 Operating System Security
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Computer System Components Hardware Provides basic computing resources Ex: CPU, memory, I/O devices Operating System Controls and coordinates the use of the hardware among the various application programs. Ex: windows ,Unix , Linux etc. Applications : Define the ways in which the system resources are used to solve the computing problems of the users. Ex: Database, Text editor Compiler etc. Users E.g., people, machines, other computers.
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Abstract View of System Components
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Operating System: tasks Three major tasks Operating systems must provide efficient resource mechanisms , Second, it is the operating system’s responsibility to switch among the processes fairly Third, access to resources should be controlled, such that one process cannot inadvertently or maliciously impact the execution of another.
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Security Goals : Operating System Goal :1 Enabling multiple users securely share a computer Separation and sharing of processes, memory, files, devices etc. How to achieve the security goals? Memory protection Processor Security User authentication File access control
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Security Goals : Operating System Goal: 2 ensure secure operation in networked Environment How to achieve the security goals? Authentication Access Control Secure Communication (using cryptography) Logging & Auditing Intrusion Prevention and Detection Recovery
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Process Security Ensures that one user’s process cannot access other’s memory fence – fence Relocation base/bounds register Segmentation Paging Operating system and user processes need to have different privileges
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Process Security
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Memory and File System Security Memory Protection: access control to memory Ensures that one user’s process cannot access other’s memory fence – fence relocation base/bounds register segmentation paging Operating system and user processes need to have different privileges
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System mode System mode (privileged mode, master mode, supervisor mode, kernel mode) Can execute any instruction Can access any memory locations, e.g., accessing hardware devices, Can enable and disable interrupts, Can change privileged processor state, Can access memory management units, Can modify registers for various descriptor tables .
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User mode Access to memory is limited, Cannot execute some instructions Cannot disable interrupts, Cannot change arbitrary processor state, Cannot access memory management units Transition from user mode to system mode must be done through well defined call gates (system calls)
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