Network Security Overview

Network Security Overview

• Network security protects a network's infrastructure from cyberattacks and data loss, using technologies, policies, and procedures. This includes protecting communications infrastructure.

Security Goals

• Confidentiality: Protecting sensitive information from unauthorized access. This is crucial for military operations (e.g., concealing sensitive data) and industry (e.g., protecting information from competitors). It's the most important aspect of information security. Organizations must guard against attacks endangering confidentiality.
• Integrity: Ensuring that information can only be changed by authorized entities. Unwanted changes can happen due to system disruptions (e.g., power outages). Information needs constant change, but changes must be by authorized parties.
• Availability: Guaranteeing authorized access to the needed information. Information is useless if not accessible. Unavailability is as damaging as confidentiality and integrity breaches. The information created and stored by an organization needs access by authorized entities.

OSI Security Architecture

• The OSI Security Architecture evaluates an organization's security needs through security products and policies. Focuses on attacks, mechanisms, and services.
  • Security Attacks: Any actions compromising an organization's information security. These fall into two categories:
    • Passive Attacks: Aim to obtain transmitted information.
      • Snooping: Unauthorized access or interception of data (e.g., intercepting file transfers containing confidential information).
      • Traffic Analysis: Obtaining information by monitoring online traffic (e.g., analyzing requests and responses to understand transactions).
    • Active Attacks: Aim to interfere with the target, damaging or gaining unauthorized access.
      • Repudiation: Sender denies sending a message, or receiver denies receiving (e.g., messages from a sender being denied by the sender).
      • Masquerading: Attacker pretends to be another entity to access data/systems (e.g., stealing bank card information and pretending to be the rightful owner).
      • Modification: Altering information after accessing it to make it beneficial to the attacker (e.g., customers' requests modified to cause fraudulent transactions).
      • Replaying: Attacker obtains a message copy and later replays it (e.g., a request to a bank for payment is replayed by an attacker).

Security Mechanisms

• Encipherment: Providing confidentiality through cryptography and steganography.
  • Cryptography: Converting a message into an unreadable format using symmetric or asymmetric methods.
  • Steganography: Hiding information within another message or object (e.g., altering pixels in an image).
• Digital Signature: Allows electronic signing and verification.
• Routing Control: Continuously changing routes between sender and receiver to prevent interception.
• Access Control: Determining user access rights (e.g., passwords, PINs).
• Authentication Exchange: Verifying entities' identities through message exchanges.

Security Services

• Data Confidentiality: Protecting data from disclosure (snooping, traffic analysis).
• Data Integrity: Protecting data from modifications, insertions, deletions, or replaying.
• Authentication: Verifying sender/receiver identities (connection-oriented/connection-less).
• Non-Repudiation: Preventing denial of data delivery, providing proof of origin.
• Access Control: Preventing unauthorized data access and actions.