Domain 5: Security Architecture and Design Flashcards
What is RAM?
RAM (Random Access Memory): Volatile hardware memory that loses integrity after loss of power.
What is aReference Monitor?
Reference Monitor: Mediates all access between subjects and objects.
What is ROM?
ROM (Read Only Memory): Nonvolatile memory that maintains integrity after loss of power.
What is TCSEC?
TCSEC (Trusted Computer System Evaluation Criteria): Known as the Orange Book.
What is TCB?
TCB (Trusted Computer Base): The security relevant portions of a computer system.
What is Virtualization?
Virtualization: An interface between computer hardware and the operating system that allows multiple guest operating systems to run on one host computer.
What are the two things that Security Architecture and Design describes?
1: fundamental logical hardware, operating system and software security components
2: How to use those components to design, architect and evaluate secure computer systems.
What are the three Domain Parts to Security Architecture and Design describes?
1: Hardware and software required to have secure computer system
2: Logical models required to keep the computer secure
3: Evaluation models that quantify how secure a system really is
What does
Secure System Design represent?
universal best practices; It transcends specific hardware and software implementations.
What is layering?
Separates hardware and software functionality into modular tiers.
What networking protocol isi similar to layering by profiding a similar function?
TCP/IP
Explain how layeriing works when in your systej when you change disk drives from IDE to SCSI
Example: A disk drive in the hardware layer has changed from IDE to SCSI. The device drivers in the adjoining layer will also change but the other layers in the Operating System and the Application layers will remain unchanged.
What are the generic names for the four layers?
1: Hardware
2: kernel and device drivers
3: Operating System
4: Applications
Why is abstraction a good design principal?
Complexity is the enemy to security and computers are extremely complex machines.
Why does abstraction provide the user?
Abstraction hides unnecessary detail from the user and provides a way to manage that complexity.
In the context of Secure System Design Concepts, Name two definitions for a a Securitiy Domain?
1: A list of objects a subject is allowed to access.
2: Groups of subjects and objects with similar security requirements like CONFIDENTIAL, SECRET and TOP Secret or User Mode and kernel Mode.
What does kernel mode provide access to?
Allows low-level access to hardware (memory, CPU, disk, etc).
Most trusted and powerful part of the system.
What is another name for does kernel mode ?
Supervisor Mode
What is The Ring Model?
A form of CPU layering that separates and protects domains from each other.
What are the four generic names to the the Ring Model layers?
Ring 0: Kernel
Ring 1: Other OS components that do not fit into Ring 0
Ring 2: Device Drivers
Ring3: User Applications
What is the name for the process for communicting between layers in the Ring Model?
System Calls
What is one advantage and one disadvantage to System Calls?
System Calls are slow compared to inner ring communication but provide security.
Practically, why do most X86 CPUs, including Linux and Windows, only use Ring 0 and Ring 3
because of performance issues.
What Ring Layer does a Hypervisor operate in?
Hypervisor (Ring 1)
Allows virtual guests to operate in Ring 0.
What is the difference beetween an Open and Closed System?
An open system uses open hardware and standards from a variety of vendors.
A closed system uses proprietary hardware.
What is the difference beetween an Open system and Open Source?
An open system uses open hardware and standards from a variety of vendors.
Open source makes source code publicly available.
What is the difference beetween The System Unit and the Motherboard?
System Unit: The case and all the internal electronic computer parts including the motherboard, disk drives, power supply, etc.
Motherboard: hardware components like the CPU, memory slots, firmware, and peripheral slots
What is the purpose of The Computer Bus?
Primary communications channel between all components.
Some systems have two buses. What are thier names?
Northbridge & Southbridge: Two buses
What does each bus (Northbridge & Southbridge) propvide the communication channels for?
- *Northbridge**
1: Memory Controller Hub – MCH)
2: Connects CPU to RAM and Video Memory
The Northbridge Bus is directly connected to the CPU and is faster than southbridge
Southbridge
1: I/O Controller Hub – ICH)
2: Connects input/output devices.
What does the acronym MCH stand for?
Memory Controller Hub – MCH
What does the acronym ICH stand for?
I/O Controller Hub – ICH
What does the acronym CPU stand for?
Central Processing Unit
What is the difference between the Arithmetic Logic Unit (ALU) and Control Unit?
ALU performs mathematical calculations
Control Unit feeds instructions to the ALU
What does the acronym ALU stand for?
Arithmetic Logic Unit
What is another name for Fetch & Execute?
Also called Fetch – Decode – Execute (FDX)
What does the acronym FDX stand for?
Fetch – Decode – Execute (FDX)
What are the generic four steps to the Fetch & Execute clock cycle?
1: Fetch Instruction 1
2: Decode Instruction 1
3: Execute Instruction 1
4: Write (save) Result
What is Pipelining?
Combines multiple steps into one process allowing simultaneous FDX and increasing throughput.
What is the pipeline depth?
The pipeline depth is the number of simultaneous stages which may be completed at once.
What is an Interrupt?
Indicate that an asynchronous event has occurred that causes the CPU from processing its current task, save the state, and begin processing a new request.
When the new task is complete, the CPU will complete the prior task.
What is a Process?
An executable program and its associated data loaded and running in memory.
What is a Heavy Weight Process called?
(HWP) is called a task.
What is a Light Weight Process called?
LWP is called a thread
What does the acronym LWP stand for?
Light Weight Process
What does the acronym HWP stand for?
Heavy Weight Process
What is the differenece between Heavy Weight Processes and Light Weight Processes?
HWPs do not share memory while LWPs share memory resulting in low overhead.
What is a thread?
A Parent process may spawn child processes called Threads.
What is a zombie process?
A child process whose parent has terminated.
What are the five process states?
1: New: A process being created
2: Ready: Processes waiting to be executed by the CPU
3: Running: Processes being executed by the CPU
4: Blocked: Processes waiting for I/O
5: Terminated: Process that are complete.
What is Multitasking?
Multitasking: Allows multiple HWP (Heavy Weight Processes) to run simultaneously on one computer.
What is Multiprogramming?
Allows multiple programs to run simultaneously on one computer.
What is Multithreading?
Multithreading: Allows multiple LWP (Light Weight Processes - threads) to run simultaneously on one computer.
What is Multiprocessing?
Multiprocessing: Allows multiple processes to run simultaneously on multiple CPUs.
What is Symmetric Multiprocessing (SMP)?
Symmetric Multiprocessing (SMP): One operating system manages all CPUs.
What is Asymmetric Multiprocessing (ASMP or AMP)?
Asymmetric Multiprocessing (ASMP or AMP): One operating system essentially all independent systems.
Name the six types of “Multi” processing schemes:
1: Multitasking: Allows multiple HWP (Heavy Weight Processes) to run simultaneously on one computer.
2: Multiprogramming: Allows multiple programs to run simultaneously on one computer.
3: Multithreading: Allows multiple LWP (Light Weight Processes - threads) to run simultaneously on one computer.
4: Multiprocessing: Allows multiple processes to run simultaneously on multiple CPUs.
5: Symmetric Multiprocessing (SMP): One operating system manages all CPUs.
6: Asymmetric Multiprocessing (ASMP or AMP): One operating system essentially all independent systems.
What is a Watchdog Timer?
Watchdog Timer: Design to recover a system by rebooting after critical processes hang.
What is the difference between CISC and RISC architectures??
CISC (Complex Instruction Set Computer): Low-level commands are longer and powerful using less individual instructions to perform a complex task.
RISC (Reduced Instruction Set Computer): Low-level commands are shorter and simpler using more individual instructions to perform a complex task but allowing less cycles per instruction and more efficient code.
What does the acronym CISC stand for?
CISC (Complex Instruction Set Computer): Low-level commands are longer and powerful using less individual instructions to perform a complex task.
What does the acronym RISC stand for?
RISC (Reduced Instruction Set Computer): Low-level commands are shorter and simpler using more individual instructions to perform a complex task but allowing less cycles per instruction and more efficient code.
Which architecture is best: RISC or CISC?
No correct answer
CISC used in x86 CPUs
RISC used in smart phones, powerPCs, SPARC
Which architecture is best: RISC or CISC?
No correct answer
CISC used in x86 CPUs
RISC used in smart phones, powerPCs, SPARC
What does the acronym RAM stand for?
Random Access memory
Is RAM volatile?
Yes but some RAM has remanence for seconds or minutes after loss.
What os Sequential memory?
Like a tape, must sequentially read memory.
What is memory Volatility?
Like RAM, loses integrity after power loss.
What is memory Nonvolatility?
Like ROM, Disk or tape, does not lose integrity after power loss.
What does the acronym ROM stand for?
ROM (Read Only Memory).
What is the main difference between ROM and RAM?
ROM is Nonvolatile while RAM is volatile.
Can you overwrite ROM?
Yes - Some types of ROM may be overwritten in a process called flashing
What is Real or Primary Memory?
Real or Primary: Like RAM, directly accessible by the CPU and is used to hold data and instructions for currently running processes.
What is Secondary Memory?
Secondary: Like disks, is not directly accessible.
What is Cache?
Fastest memory on the system, the data most frequently used by the CPU.
Name the five types of cache in order of speed.
1: Register File: The fastest portion of the cache, small storage locations used to store instructions and data.
2: Level 1: Next Fastest, Located on the CPU.
3: Level 2: Next Fastest, connected to the CPU but Located outside.
4: SRAM (Static Random Access Memory): Expensive and Fast, uses small latches called flip-flops to store bits.
5: DRAM (Dynamic Random Access memory):: Stores bits in small capacitors (like batteries) and is slower and cheaper than SRAM.
In regards to cache, what is a Register File?
Register File: The fastest portion of the cache, small storage locations used to store instructions and data.
In regards to cache, what is Level 1 cache?
Reallyy fast memory Located on the CPU.
In regards to cache, what is Level 2 cache?
Reallyy fast memory Located outside the CPU but directly connected.
In regards to cache, what is SRAM?
SRAM (Static Random Access Memory): Expensive and Fast, uses small latches called flip-flops to store bits.
What does the acronym SRAM stand for?
SRAM (Static Random Access Memory):
What does the acronym DRAM stand for?
Dynamic Random Access memory
What does the acronym DRAM stand for?
Dynamic Random Access memory
In regards to cache, what is DRAM memory?
Stores bits in small capacitors (like batteries) and is slower and cheaper than SRAM.
Leak charge and must be refreshed
What is the difference between asynchronous and synchronous SRAM?
Synchronous SRAM is designed to exactly match the speed of the CPU, while asynchronous is not. That little bit of timing makes a difference in performance. Matching the CPU’s clock speed is a good thing, so always look for synchronized SRAM.
What is the General Rule cache and location to the CPU?
General Rule: the closer memory is to the CPU, the faster and more expensive it is. As you move away from the CPU (SRAM, DRAM to Disk, tape, etc) it becomes slower and less expensive.
In terms of Memory Addressing, what is Direct Addressing?
The CPU adds the values stored here (at this memory location).
In terms of Memory Addressing, what is Indirect Addressing?
Indirect Addressing (Pointer):
The CPU adds the value stored in memory location here.
In terms of Memory Addressing, what is Register Direct Addressing?
The same as Direct Addressing except that it references a CPU register.
In terms of Memory Addressing, what is Register Indirect Addressing?
The same as InDirect Addressing except the pointer is stored in the register.
What is Memory Proteection?
Prevents one process from affecting the CIA of other processes.
What is Memory design requirement for secure multiuser and multitasking systems.
Memory Protection
In terms of Memory Protection,
What is Process Isolation?
A logical control that attempts to prevent one process from interfering with another.
In terms of Memory Protection,
Why is Process Isolation important?
A lack of process isolation means that one process crash could crash the entire operating system or that an attacker could affect the CIA of any transaction
In terms of Memory Protection,
What is an Interference attack?
Interference attacks are CIA attacks on process isolation.
In terms of Memory Protection,
what is one exampleof an interferenceattack for each element of CIA?
Confidentiality: read your credit card number during an online purchase.
Integrity: Change your credit card number during an online purchase
Availability: Stopping an online purchase
In terms of Memory Protection,
what are the four techniques used to provide process isolation
1: Virtual memory
2: Object Encapsulation
3: Time Multiplexing
4: Hardware Segmentation
In terms of Memory Protection,
how does Virtual Memory provide Process Isolation?
Provides virtual address mapping between applications and hardware memory.
where process A’s address space is different from process B’s address space - preventing A to write into B.
In terms of Memory Protection,
Is the function of Virtual Memory only Process Isolation?
No - it has Multiple Functions:
1: Multitasking (multiple tasks on one CPU)
2: Shared library for multiple processes
3: Swapping
What are the three functions of Virtual Memory?
1: Multitasking (multiple tasks on one CPU)
2: Shared library for multiple processes
3: Swapping
Is Virtual Memory = Swapping?
No - it has three functions:
1: Multitasking (multiple tasks on one CPU)
2: Shared library for multiple processes
3: Swapping
In terms of Virtual Memory,
What is paging?
Paging: Copies blocks of memory between RAM and secondary memory.
In terms of Virtual Memory,
What is swap space?
Swap space is often a dedicated partition on the hard drive and is used to extend the amount of available memory.
In terms of Virtual Memory,
What is a page fault?
If the kernel attempts to access a page (fixed-length block of memory) located in swap space, a page fault occurs telling the computer to swap the page from the Swap Space into RAM.
In terms of Virtual Memory,
What is a swapping designed to do?
Designed as a protective measure to handle occasional bursts of memory usage.
In terms of Virtual Memory,
What is the generic process for swapping?
1: Computers keep filling RAM until almost filled.
2: The system will Swap idle processes to Swap Space.
3: As both RAM and Swap Space fills up, the system will start thrashing by swapping active processes to Swap space.
In terms of Virtual Memory,
What is thrashing?
As both RAM and Swap Space fills up, the system will start thrashing by swapping active processes to Swap space.
In terms of Virtual Memory,
What is are two mitigations to thrashing?
1: Add more memory
2: Remove processes
In terms of Virtual Memory,
What is firmare?
Stores small programs that do not change that often in ROM.
In terms of Virtual Memory,
What are the three types of firmare?
1: PROM (Programmable Read Only Memory): Can be written once typically at the factory.
2: EPROMS (Erasable Programmable Read Only Memory):
3: EEPROMS (Electrically Erasable Programmable Read Only Memory):
In terms of Virtual Memory and firmware
What is a PROM?
PROM (Programmable Read Only Memory): Can be written once typically at the factory.
In terms of Virtual Memory and firmware
What is a EPROM?
Erasable Programmable Read Only Memory that May be flashed or erased or written many times.
In terms of Virtual Memory and firmware
Where did the term Flashing come from?
Flashing derived from EPROMs because they were erased by flashing ultraviolet light onto a small window on the chip.
In terms of Virtual Memory and firmware
What is Flashing?
Flashing is the process of erasing and re-writing EPROMs.
In terms of Virtual Memory and firmware
What is an EEPROM?
EEPROMS (Electrically Erasable Programmable Read Only Memory): May be flashed or erased or written many times
In terms of Virtual Memory and firmware
What is the difference between a EPROM and an EEPROM?
EEPROMS are a Modern type of ROM, electrically erasable via flashing programs.
Any byte of a EEPROM can be overwritten.
In terms of Virtual Memory and firmware
What is the difference between a EPROM and an EEPROM?
EPROMs can be flashed but it is all or nothing.
EEPROMS are a Modern type of ROM, electrically erasable via flashing programs. Any byte of a EEPROM can be overwritten.
In terms of Virtual Memory and firmware
What is Programmable Logic Device (PLD):
Programmable Logic Device (PLD) are programmed after it leaves the factory.
In terms of Virtual Memory and firmware
Name three types of Programmable Logic Devices (PLDs)
1: EPROMS
2: EEPROMS
3: Flash memory are all PLDs.
In terms of Virtual Memory and firmware
What is the issue with destroying firmware as compared to other electronics?
Chip-based media is not like magnetic disks; Degausers may not work.
In terms of Virtual Memory and firmware
What does the acronym BIOS stand for?
Basic Input Output System
In terms of Virtual Memory and firmware
What is a BIOS?
Code in firmware that is executed when the PC is turned on,
In terms of Virtual Memory and firmware
What does the acronym WORM stand for?
WORM (Write Once Read Many) Storage