Secure System Design

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Trusted OS

Trusted Computing Base

the kernel and associated hardware and processes must be designed to support the enforcement of a security policy

Security Features

support for multilevel security

Assurance

secure design principles, availability of code reviews and audits

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Root of Trust

Definition

a secure subsystem that is able to provide proof it is trustable

usually established by a type of cryptoprocessor called a Trusted Platform Module

Trusted Platform Module

specification for hardware-based storage of digital certificates, keys, hashed passwords, and other user and platform identification information

functions as an embedded smart card

implemented either as part of the chipset or as an embedded function of the CPU.

microprocessor is hard-coded with a unique, unchangeable RSA private key

endorsement key is used to create numerous other subkeys of various types, for use in key storage, signature, and encryption operations.

compares hashes of key system state data (boot firmware, boot loader, and OS kernel) to ensure they have not been tampered with.

Supply Chain

for provisioning the computing device to the end user must all be trustworthy

denying malicious actors the time or resources to modify the assets being supplied.

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BIOS

Definition

provides industry standard program code that operates the essential components of the PC

ensures that the design of each manufacturer's motherboard is PC compatible.

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UEFI

Definition

used for newer motherboards

support for 64-bit CPU operation at boot, a full GUI and mouse operation at boot, and better boot security.

Secure Boot

security system offered by UEFI

to prevent a computer from being hijacked by a malicious OS.

configured with digital certificates from valid OS vendors

checks the operating system boot loader using the stored certificate to ensure that it has been digitally signed by the OS vendor preventing it from being modified by malware

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Drive Encryption

Full Drive Encryption

means that the entire contents of the drive (or volume), including system files and folders, are encrypted

requires the secure storage of the key used to encrypt the drive contents

Drawbacks

causes a performance hit

is mitigated by Self-Encrypting Drives (SED)

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Server and Application Hardening

Definition

apply the principle of “running only services (or application features) that are required

Kiosks

deployed to a public environment

providing ATM services or airport check-in, as well as informational kiosks used in shopping centers, art galleries, and museums

hardware is fully locked down

Execution control

process of determining what additional software may be installed on a client or server beyond its baseline

prevent the use of unauthorized software can be implemented as either a whitelist or a blacklist

Blacklist e.x. antivirus

Whitelist e.x. App store

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Removable Media Control

§might be a vector for malware, either through the files stored in the media or its firmware

means of exfiltrating data.