trojans

usable on Intel and ARM processors architectures

both available on iOS

removable devices

identical

viruses

common passwords

open-source technologies

respectively software and hardware

malwares

usable only on ARM

embedded in smartphones

usable only on Intel

both available on Android

Malwares

Removable devices

Passwords

Firewalls

Trojans

Smartphones

Administrators of information systems

Users of information systems

Networks

Quantum-resistant encryption

Viruses

Defining which protocols and hosts and networks are not allowed

Filtering only outgoing traffic

Using only an external firewall

Filtering only incoming traffic

Filtering only forwarding traffic

doing filtering and QoS settings jointly

only filtering an no QoS setting

Defining which protocols and hosts and networks are allowed and at which conditions

Check that installed software is always updated at the latest version

Add honeypots to mislead attackers

Act as a firewall

Monitor activity and identify possible attacks

Collect logs

Isolate critical components of the infrastructure in case of threat detection

Provide analysis of traffic and issue reports

Provide cybersecurity advice to administrators and users of the system

Send messages to possible attackers warning them about legal issues

Provide better security

Provide detection of attacks

Provide security fixes more rapidly

Provide evaluation of security

Provide 100% resistance to attacks

Provide security adapted to context

Provide identification of assets to protect

Provide viral immunity

local access

data encryption

network packet filtering

remote access

supervision

authentication

not available in most Linux distributions

settable only by configuration

not available in virtual machines

usable to mitigate hardware vulnerabilities such as Meltdown and Spectre

sometimes including out-of-mainstream Linux kernel developments such as GRsecurity

available only for Intel and AMD processors architectures

mostly proprietary

settable by dynamic parameters

Latest Google Pixel

Red telephone from cold war years between presidents of USA and USSR

Android phone from 7 years ago

Latest iPhone

wired phone from around year 1980

Nokia GSM phone from around year 2000

iPhone from 7 years ago

Dark web

All of the above

Web forums

Public organisations such as ANSSI, NIST, BSI, CERT, MITRE, ...

Some well-known sites such as Verizon, Thales, Orange ...

Any web site that appears well documented on this subject

Higher levels of security (EAL6 and 7) are only achieved for isolated systems

From hardening perspective, hardware is always trustable

OS hardening of non-critical systems is never needed

From a security perspective OS hardening is not as important as application hardening

100% secure system is not achievable

Hardening is mostly quantitative whereas security is not

Formal methods are needed for the highest level of security (EAL7)

Security of a system always decreases along time