3.4 BIOS/UEFI Flashcards
Aside from starting the computer system, what else is the BIOS used for?
Configuring the motherboard using a text-based interface
What is firmware?
Software that provides basic machine instructions that allow the hardware to function and communicate with other software running on a device
What does the UEFI do that the BIOS doesn’t?
Supports 64-bit processors and provides a GUI
Where is the BIOS program code stored?
In the flash memory of the motherboard (the CMOS)
List three boot options
- Power-on self test
- Hardware configuration
- Boot order setup
What is ROM (Read-only memory)
A chip embedded in the motherboard that can be upgraded through flashing
What sort of battery does the new CMOS use and how long can it last for?
An internal lithium-ion battery that can last up to 10 years
Why would you use a POST?
To perform a testing sequence to check the computer’s BIOS
How does the computer communicate what is wrong with the system during a POST?
Through variable beeps
What are some improvements UEFI made to BIOS?
Supports large harddrives and more memory
Graphical, mouse-supporter user interface
Can access network connection to download updates
Faster boot-up system
Supports 64-bit systems
Supports new GUID Partition Table (GPT) format
What are some settings you can change in the UEFI?
- Disable booting from an optical or USB drive
- Configure system to boot from installed harddrive using installed OS
- Boot OS using PXE (preboot execution environment) as the primary option
When would you perform flashing?
During upgrades, security fixes, or feature improvements
List the steps you would take during flashing
- Backup configuration and information
- Use USB flashdrive to flash the firmware
- The BIOS or UEFI will copy the firmware to the system and overwrite the old code
Where is the boot information held for computers relying on BIOS and UEFI, respectively?
BIOS - MBR (Master Boot Record)
UEFI - GPT (Globally Unique ID Partition Table)
What does a supervisor/admin/setup password do?
Protects the BIOS/UEFI configuration program from access by unauthorised users
What does the user/system password restrict access to?
The computer
What doees the storage/harddrive password do?
Locks access to a harddrive connected to the system
What is secure boot?
A standard ensuring the computer only boots with trusted software; only available for UEFI
What is a rootkit?
A special type of malware designed to enable access to a computer or area of its software that is not otherwise allowed
List some precautions you might take to protect against rootkits being downloaded onto a computer
Set passwords
Enable secure boot
Restrict/disable USB ports
What is the Hardware Root of Trust (RoT)?
A cryptographic module embedded in a computer system that endorses trusted execution and attests to boot settings and metrics
What does a hardware RoT do?
Scans boot metrics in OS files to verify signatures and then uses them to sign the report
What is TPM (Trusted Platform Module)?
(not counting the chip)
Specification for hardware-based storage of digital certificates, keys, hashed passwords, and other user and platform identification information
How can you manage a TPM?
In Windows via tpm.msc console, or through group policy
List some features of TPM
- Hardware RoT
- Secure boot-up
- Provides encryption
What is a HSM (Hardware Security Module)?
An appliance for generating and storing cryptographic keys that is less susceptible to tampering and inside threats
What is the difference between a TPM and HSM?
TPM is a chip on the computer’s motherboard whereas HSM is an external device
What would generate excess heat?
Overclocking the processor
What physical part of a computer do the BIOS and UEFI have the ability to configure?
Fans - Quiet, balanced or cool mode.
When would you use quiet mode, and when would you use cool mode for the fan?
Quiet - To allow higher temperatures to occur
Cool - To create more air flow
What is a heatsink?
Any device used to cool system components (notably CPU, GPU and power supply)
Give some examples of heatsinks
- Aluminium alloy radiator for chips
- Liquid-based (water, reservoir and pump)
- Passive heat sink
Name some ways apart from heatsinks to keep computers cool
- Thermal paste (produces better conduction between components)
- Standard aircon
