Operating Systems and Security Quiz 30 MCQ || MID Term
Operating Systems and Security Quiz
Q1. Which component of the CPU is listed alongside the General purpose registers, Program counter, and Stack pointer?
a) ALU
b) Control Unit (CU)
c) Program Status Word (PSW)
d) Disk Controller
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Answer : c) Program Status Word (PSW)Q2. According to the sources, which type of memory is explicitly described as "Small Volatile"?
a) ROM
b) Flash memory
c) EEPROM
d) DRAM
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Answer : d) DRAMQ3. In the context of the Operating System views, what is the OS described as when acting as an interface between the user and Hardware?
a) Resource manager
b) Control program
c) Extended machine / User view
d) Kernel program
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Answer : c) Extended machine / User viewQ4. Which architectural concept is discussed concerning the organization of the CPU, Memory, and Buses?
a) RISC Architecture
b) Von Neumann Architecture
c) Harvard Architecture
d) Microkernel Architecture
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Answer : b) Von Neumann ArchitectureQ5. What is the primary design goal for the Operating System in a Mainframe computer environment?
a) Designed for ease of use
b) Designed to compromise usability and resource utilization
c) Designed to maximize resource allocation
d) Designed to provide touch screen functionality
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Answer : c) Designed to maximize resource allocationQ6. Which of the following is listed as a modern bus used in systems?
a) Control bus
b) Address bus
c) QuickPath Interconnect (QPI)
d) Parallel bus
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Answer : c) QuickPath Interconnect (QPI)Q7. One of the three major tasks of an Operating System is to provide switching among processes fairly, such that the use experience good performance, and the third major task is to ensure the security of all processes by controlling what?
a) Malicious access of a process’s resources by other processes
b) Unauthorized resource consumption
c) Exhaustion of I/O devices
d) Kernel module loading
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Answer : a) Malicious access of a process’s resources by other processesQ8. Which security requirement limits the objects that individual subjects can read because objects may contain secrets not all subjects are permitted to know?
a) Integrity
b) Availability
c) Confidentiality/Secrecy
d) Verification
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Answer : c) Confidentiality/SecrecyQ9. Which security goal limits the system resources (e.g., storage and CPU) that subjects may consume?
a) Confidentiality
b) Integrity
c) Availability
d) Mediation
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Answer : c) AvailabilityQ10. What defines the set of software and data upon which the system depends for correct enforcement of system security goals?
a) Reference Monitor
b) Protection Domain
c) Threat Model
d) Trusted Computing Base (TCB)
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Answer : d) Trusted Computing Base (TCB)Q11. What is the traditional statement used to describe system access?
a) Resources, Labels, and Policies
b) Subjects, Operations, and Objects
c) TCB, Kernel, and Processes
d) Read, Write, and Execute
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Answer : b) Subjects, Operations, and ObjectsQ12. To prove an OS has a viable trust model, it must be verified that the software’s execution cannot be tampered with by processes outside of what?
a) The system kernel
b) The TCB
c) The application layer
d) The root processes
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Answer : b) The TCBQ13. Which concept defines the set of resources (objects) that a process can access and the operations that the process may use to access such resources?
a) Trusted Computing Base (TCB)
b) Access Matrix
c) Protection domain
d) Access Control List (ACL)
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Answer : c) Protection domainQ14. In Lampson’s Access Matrix model, which special operation defines ownership operations for an associated object, allowing the subject to modify other cells related to that object?
a) Delegate
b) Own
c) Update
d) Revoke
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Answer : b) OwnQ15. What is the fundamental problem associated with Discretionary Access Control (DAC) systems like Lampson's model, concerning the undecidable nature of preventing future unauthorized access?
a) The Delegation problem
b) The Integrity problem
c) The Safety problem
d) The Resource allocation problem
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Answer : c) The Safety problemQ16. A Mandatory Protection System is defined as a system that can only be modified by trusted administrators via trusted software, and where subjects and objects are represented by what?
a) File Descriptors
b) Labels
c) Capabilities
d) UIDs and GIDs
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Answer : b) LabelsQ17. The assignment of permissions to a label in a Mandatory Protection System defines its:
a) Verification standard
b) Mutability status
c) Security semantics
d) Transition state
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Answer : c) Security semanticsQ18. Which component of the Reference Monitor performs the function of checking whether a request is authorized by the access control policy?
a) Interface
b) Authorization module
c) Policy store
d) Protection state
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Answer : b) Authorization moduleQ19. Which of the following is NOT one of the three guarantees defining the Reference Monitor concept necessary for a secure operating system?
a) Complete mediation
b) Tamperproof
c) Decentralized control
d) Verifiable
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Answer : c) Decentralized controlQ20. Verifying that a reference monitor is tamper proof requires verifying that all its components cannot be modified by processes outside of what?
a) The user program space
b) The system's trusted computing base (TCB)
c) The kernel mode
d) The network stack
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Answer : b) The system's trusted computing base (TCB)Q21. UNIX was developed by Dennis Ritchie and Ken Thompson and is noted historically as the first portable OS because it was written in which language?
a) Assembly
b) C++
c) Java
d) C
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Answer : d) CQ22. In UNIX, what concept is used to represent all persistent system objects, including secondary storage, I/O devices, network, and IPC communication?
a) Process
b) File
c) Socket
d) Descriptor
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Answer : b) FileQ23. The UNIX Trusted Computing Base (TCB) consists of the kernel and several other processes that run with the identity of which privileged user?
a) Superuser (root)
b) Owner UID
c) Administrator GID
d) System user
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Answer : a) Superuser (root)Q24. A UNIX process identity consists of a User ID (UID), a Group ID (GID), and what else?
a) A set of access control lists (ACLs)
b) An owner UID
c) A set of supplementary groups
d) A protection domain label
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Answer : c) A set of supplementary groupsQ25. In the UNIX mode bits representation `rwxr--r--`, what access rights does a process with a GID or supplementary group corresponding to the file's group have?
a) Read, Write, and Execute
b) Read only
c) Write only
d) No access
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Answer : b) Read onlyQ26. What happens when the `setuid` bit is set on a file that a process executes?
a) The process is restricted to running in user mode.
b) The process automatically performs a protection domain transition to the file’s owner UID and group GID.
c) The process is forced to run under the kernel's identity.
d) The process gains mandatory access control rights.
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Answer : b) The process automatically performs a protection domain transition to the file’s owner UID and group GID.Q27. When a file is opened and authorization is successful, UNIX creates what kernel-stored item that represents the process’s authorized access to perform future operations on the file, acting as a form of capability?
a) Process ID (PID)
b) File descriptor
c) Capability List (c-list)
d) Access Matrix cell
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Answer : b) File descriptorQ28. Which type of vulnerability arises when TCB processes, such as network-facing daemons (`sshd`, `ftpd`), maintain open network ports, potentially allowing attackers to exploit flaws in handling incoming data?
a) Environment Variable attacks
b) Shared Resource attacks
c) Buffer overflow attacks
d) Rootkit installation
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Answer : c) Buffer overflow attacksQ29. What type of malicious package takes advantage of kernel module loading or other interfaces available to root processes to execute code with full system privileges?
a) Network-facing daemons
b) Rootkits
c) Format strings
d) Buffer overflow visualizations
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Answer : b) RootkitsQ30. A common UNIX vulnerability involves an untrusted process changing which system variable to load an attacker-provided file as a dynamic library, especially if a TCB process inherits this variable?
a) PATH
b) TCB_VAR
c) LIBPATH (Example)
d) UID
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