Chapter 9- Security Vulnerabilities, Threats and Countermeasures Flashcards
- What is hardware?
Hardware: The term hardware encompasses any tangible part of a computer that you can actually reach out and touch, from the keyboard and monitor to its CPU(s), storage media, and memory chips.
- What do you understand by the Processor?
The central processing unit (CPU), generally called the processor or the micro-aprocessor.
It is the computer’s nerve center—
it is the chip (or chips in a multiprocessor system) that governs all major operations and either directly performs or coordinates the complex symphony of calculations that allows a computer to perform its intended task.
- List Execution Types
- Multi tasking
- Multicore
- Multiprocessing
- Explain Multicore
This means that what was previously a single CPU or microprocessor chip is now a chip containing two, four, eight, or potentially dozens of independent execution cores that can operate simultaneously.
- Define Multitasking:
In computing, multitasking means handling two or more tasks simultaneously.
- Define Massively Parallel Processing (MPP):
MPP systems house hundreds or even thousands of processors, each of which has its own operating system and memory/bus resources.
MPP systems are extremely powerful (not to mention extremely expensive!) and are used in a great deal of computing or computational-based research.
- Explain Multiprogramming:
: Multiprogramming is similar to multitasking. It involves the pseudosimultaneous execution of two tasks on a single processor coordinated by the operating system as a way to increase operational efficiency. Multiprogramming is considered a relatively obsolete technology and is rarely found in use today except in legacy systems.
- Differences between multiprogramming and multitasking.
Multiprogramming usually takes place on large-scale systems, such as mainframes,
whereas multitasking takes place on personal computer (PC) operating systems, such as Windows and Linux.
Multitasking is normally coordinated by the operating system, whereas multiprogramming requires specially written software that coordinates its own activities and execution through the operating system.
- Define Multithreading:
Multithreading permits multiple concurrent (simultaneous or coinciding) tasks to be performed within a single process.
Multithreading is often used in applications where frequent context switching between multiple active processes consumes excessive overhead and reduces efficiency. In multithreading, switching between threads incurs far less overhead and is therefore more efficient
- Diff between multithreading and multitasking
multitasking, where multiple tasks occupy multiple processes, multithreading permits multiple tasks to operate within a single process.
- Define a thread
A thread is a self-contained sequence of instructions that can execute in parallel with other threads that are part of the same parent process.
- Define Single State systems:
Single-state systems require the use of policy mechanisms to manage information at different levels.
- Define Multistate systems
: Multistate systems are capable of implementing a much higher level of security. These systems are certified to handle multiple security levels simultaneously by using specialized security mechanisms known as protection mechanisms
- What are technical mechanisms
Technical mechanisms prevent information from crossing between the two users and thereby crossing between security levels.
- Explain Protection Rings
Protection rings organize code and components in an operating system into concentric rings.
The deeper inside the circle you go, the higher the privilege level associated with the code that occupies a specific ring. Most modern operating systems use a four-ring model (numbered 0 through 3).
As the innermost ring, 0 has the highest level of privilege and can basically access any resource, file, or memory location. The part of an operating system that always remains resident in memory (so that it can run on demand at any time) is called the kernel.
- Explain Ring 0 of the protection ring:
As the innermost ring, 0 has the highest level of privilege and can basically access any resource, file, or memory location. The part of an operating system that always remains resident in memory (so that it can run on demand at any time) is called the kernel.
It occupies ring 0 and can pre-empt code running at any other ring.
- Explain ring 1 of the protection ring
The remaining parts of the operating system—those that come and go as various tasks are requested, operations performed, processes switched, and so forth—occupy ring 1.
- Explain Ring 2 of the protection ring:
: Ring 2 is also somewhat privileged in that it’s where I/O drivers and system utilities reside; these are able to access peripheral devices, special files, and so forth that applications and other programs cannot themselves access directly.
- Explain Ring 3 of the protection ring
Applications and programs occupy this ring
- Explain the essence of the protection ring
The essence of the ring model lies in priority, privilege, and memory segmentation.
The process associated with the lowest ring number always runs before processes associated with higher-numbered rings.
Those processes that run in higher-numbered rings must generally ask a handler or a driver in a lower-numbered ring for services they need; this is sometimes called a mediated-access model.
- In practice, many modern operating systems break memory into only two segment explain them
one for system-level access (rings 0 through 2), often called kernel mode, supervisory mode or privileged mode
and one for user-level programs and applications (ring 3), often called user mode.
- Explain the ring model from a security stand point
the ring model enables an operating system to protect and insulate itself from users and applications.
It also permits the enforcement of strict boundaries between highly privileged operating system components (such as the kernel) and less privileged parts of the operating system (such as other parts of the operating system, plus drivers and utilities).
It also permits the enforcement of strict boundaries between highly privileged operating system components (such as the kernel) and less privileged parts of the operating system (such as other parts of the operating system, plus drivers and utilities). Within this model, direct access to specific resources is possible only within certain rings; likewise, certain operations (such as process switching, termination, and scheduling) are allowed only within certain rings.
- Define Process states
process states are various forms of execution in which a process may run. It is also known as operating state
- From a security standpoint, the ring model does what?
The ring model enables an operating system to protect and insulate itself from users and applications. It also permits the enforcement of strict boundaries between high privileged operating system and less parts of the operating system.
