IT-Security (Chapter 1) Flashcards
Examples of Cyber-Physical Systems
Industrial Facilites
Smart Grid
Smart Transport
Smart Cities
Security vs. Safety
Security: Protection against intentional malice
Safety: Protection against accidental threats
Defintion of “Threat”
A threatin an IT-based system is any possible event or sequence of actions that might lead to a violation of one or more security goals
What is the Security Goal Acronym
CIAAC
Security Goal 1
Confidentiality:
Data transmitted/stored should only be revealed to intended audience
Confidentiality of entitiesis also referred to as anonymity
Security Goal 2
Integrity:
It should be possible to detect any modification of data
This requires to be able to identifythe creator of some data
Security Goal 3
Availability:
Services should be available and function correctly
Security Goal 4
Accountability:
It should be possible to identify the entity responsible for any communication event
Security Goal 5
Controlled Access:
Only authorized entities should be able to access certain services or information
Masquerade (Threats Technically Defined)
An entity claims to be another entity
Eavesdropping (Threats Technically Defined)
An entity reads information it is not intended to read
Authorization Violation (Threats Technically Defined)
An entity uses a service or resources it is not intended to use
Loss or Modification of (transmitted) information (Threats Technically Defined)
Data is being altered or destroyed
Denial of Communication Acts (Repudiation) (Threats Technically Defined)
An entity falsely denies its participation in a communication act
Forgery of information (Threats Technically Defined)
An entity creates new information in the name of another entity
Sabotage (Threats Technically Defined)
Any action that aims to reduce the availability and / or correct functioning of services or systems
Physical Security (Safeguards Against Security Threats)
Locks or other physical access control
Personnel Security (Safeguards Against Security Threats)
Employee screening processes
Security training and awareness
Administrative Security (Safeguards Against Security Threats)
Controlling import of foreign software
Emanations Security (Safeguards Against Security Threats)
Radio Frequency and other electromagnetic emanations controls
Media Security (Safeguards Against Security Threats)
Scanning media for viruses
Lifecycle Controls (Safeguards Against Security Threats)
Trusted system design, implementation, evaluation and endorsement
Computer Security (Safeguards Against Security Threats)
Protection of the computing devices itself
Communications Security (Safeguards Against Security Threats)
Protection of information during transport from one system to another
Security Services
Authentication Integrity Confidentiality Access Control Non Repudiation
Authentication (Security Service)
The most fundamental security service which ensures, that an entity has in fact the identity it claims to have
Integrity (Security Service)
In some kind, the “small brother” of the authentication service, as it ensures, that data created by specific entities may not be modified without detection
Confidentiality (Security Service)
Most popular security service, ensuring the secrecy of protected data
Access Control (Security Service)
Controls that each identity accesses only those services and information it is entitled to
Non Repudiation (Security Service)
Protects against that entities participating in a communication exchange can later falsely deny that the exchange occurred
Security Supporting Mechanisms
Key management: All aspects of the lifecycle of cryptographic keys
Event detection / security audit trail: Detection and recording of events that might be used in order to detect attacks
Intrusion detection: Analysis of recorded security data
Notarization: Registration of data by trusted third party that can confirm certain properties
Types of cryptographic algorithms
Symmetric encryption algorithms: (DES, 3DES, AES, Twofish)
Asymmetric encryption algorithms: (RSA, ElGamal)
Hash functions: (MD5, SHA1, SHA2, SHA3)
Symmetric vs. Asymmetric
Assymetric comes with high overhead
Symmetric allows higher data thoughput
Assymetric for encrypting symmetric
Message Detection Codes (MDC)
Hash of data as fingerprint to check for modifications
Message Authentication Codes (MAC)
Append a secret key 𝐾 to a message 𝑚 and hash it to ℎ(𝑚|𝐾)
Result is fingerprint of the message that cannot be forged as attackers do not know key K
