Network Security Notes

Network Security

Key Concepts

  • Authentication: Verifying the identity of a user, device, or system.
  • Authorization: Granting access rights and permissions to authenticated users.
  • Encryption: Encoding data to protect its confidentiality; requires a key to decrypt.
  • Cryptography: The study and practice of secure communication techniques, including encryption.

Authentication

  • Definition: Verifying the identity of an entity.
  • Types:
    • Password-based: Using usernames and passwords.
    • Multi-factor (MFA): Requires multiple verification factors.
    • Biometric: Uses unique biological traits.
    • Certificate-based: Uses digital certificates.
  • User Authentication: Verifies the identity of a person.
    *Knowledge-based Authentication: Something only the user knows, like a password
    *Possession-based Authentication: Something only the user has, like a physical token
    *Inherence-based Authentication: Based on biometric characteristics like a fingerprint
    *Location-based Authentication: Relies on the user's location, which can be determined using GPS, IP address, etc.
    *Behavior-based Authentication: Based on user's behavior, such as typing rhythm, mouse movement patterns, etc.
  • Machine Authentication: Verifies the identity of a device or system.
    • MAC address filtering: Allows only devices with specific MAC addresses.
    • Digital certificates: Uses certificates as proof of identity.
    • Network Access Control (NAC): Assesses device security posture before granting access.
    • Machine Passwords: Machines can also have passwords set for access.
    • MAC Address Authentication: Device is recognized by its unique MAC address.
    • IP Address Authentication: Machine is recognized by its unique IP address.
    • Hardware-based Authentication: Devices like TPM provide hardware-based cryptographic keys.
    • Device Fingerprinting: Machine has specific characteristics (like OS version, browser version, installed fonts, etc.).
    • Biometric Device Authentication: Devices have biometric features (like fingerprint scanners
    • Mutual TLS Authentication: Both the client and the server authenticate each other using Transport Layer Security (TLS) protocol.

Multi-Factor Authentication (MFA)

  • Uses multiple factors to verify identity.
  • Increases security by requiring multiple elements for authentication.

Password Policies

  • Problems with Password-Based Authentication:
    • Weak passwords.
    • Stolen or revealed passwords.
  • Organizational Approach:
    • Clear password policies.
    • Complexity requirements.
    • Minimum length requirements.
    • Mandatory resets.
    • Prohibited reuse.
    • Password Audits.
    • Reminders.

Biometric Authentication

  • Uses unique biological characteristics to verify identity.
  • Compares traits to stored data.

Encryption

  • Definition: Encoding messages to be viewed only by authorized individuals.
  • Keys:
    • Public Key: Available to everyone.
    • Private Key: Confidential to its owner.
  • Process: Data encrypted with a public key can only be decrypted by the corresponding private key, and vice versa.
    *Symmetrical Encryption: Uses the same key for both encryption and decryption of data.
    *Asymmetrical Encryption (public key encryption): Uses a pair of keys: a public key for encryption and a private key for decryption.

Challenges in Updating Security Measures

  • Change Resistance: Users resist complex or time-consuming changes.
  • Training and Education: Lack of understanding without adequate training.
  • Technology Compatibility: New practices must be compatible with existing systems.
    *Focus on usability: Choose security controls and systems that balance ease of use as well as strength.
    *Training Programs: Provide comprehensive training on new practices.
    *Phased Implementation: Introduce the changes in stages, rather than all at once

Passkeys

  • Cryptographically generated keys stored on a device
  • Uses public key cryptography and digital signatures
  • A private key generated from your digital signature public key for authentication.