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Introduction to Cybersecurity in Networks and Systems

Motivation for Cybersecurity​

  • Computers have become part of our daily life
  • We are progressively becoming more and more dependent on these tools, and many times we store and share sensitive information with others through the Internet
  • Because the Internet is a shared space, it cannot be trusted, and special security policies must be enforced by applying the right security mechanisms

CIA (Confidentiality/Integrity/Availability)​

Confidentiality:​

Definition: Absence of disclosure of data by non-authorized parties

  • Confidentiality ensures that only the right authorized parties have accessed to the information being shared

  • Security Properties:

    • Privacy
    • Segregation of privileges

Integrity:​

Definition: Absence of invalid data or system modifications by non-authorized parties

  • Integrity ensures that the data being secured can only be altered by the authorized parties

  • Security Properties:

    • Authenticity - Integrity of content and origin
    • Non-repudiation - author of information cannot deny authorship

Availability:​

Definition: Readiness of system to provide service

  • Availability ensures that a certain system that provides a service to its clients is down the least time possible

Definitions​

Vulnerability: characteristic of a system that makes it susceptible to an attack

Attack: actions that lead to a violation of a security attribute

Threat: Attack that may potentially happen; for this, we need a vulnerability, an actor and a motive (someone with a reason to attack the system)

Our mission​

  • The mission of cybersecurity specialists is to create security policies and security mechanisms to reduce the risk

Risk: Combines two parameters: The probability that something bad will happen with the damage that it will cause if it does happen

Security Policy: A security policy defines, in a shared space and for a given piece of information, who should have access to this information, and who shouldn't, establishing constraints that should be respected

Security Mechanism: A security mechanism is the tool/procedure that is used to enforce a certain security policy

Example:

  • Security Policy: All data sent to clients should not be disclosed by potential attackers spoofing the network
  • Security Mechanism: Using TLS/SSL to encrypt the communication with the clients