[Day 1] 3. Understanding Security and the CIA Triad

What is Security?

• Security ensures the Confidentiality, Integrity, and Availability (CIA Triad) of data.
• In general, security represents a state of well-being and feeling safe from harm.

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CIA Triad: The Pillars of Security

1. Confidentiality:

   • Ensures data is accessible only to authorized users.
   • Achieved through authentication methods like biometrics, passwords, or OTPs.
   • Authentication vs. Authorization:
     • Authentication: Verifies if the user is legitimate.
     • Authorization: Verifies if the user has permission to access specific resources (e.g., Linux file permissions, sticky bits).

2. Integrity:

   • Ensures that data is not altered by unauthorized users.
   • Maintains the consistency and accuracy of data.
   • Hashing: A technique to verify data integrity using hash values.
     • Example: Tools like hashcalc calculate hash values to detect data alteration during transfer.
     • checksum:
       • A checksum is a value generated from data to verify its integrity.
       • If the checksum matches at both the source and destination, the data is intact; if not, it has been altered.

3. Availability:

   • Ensures data is accessible whenever and wherever authorized users need it.
   • Resilience: Systems should perform well even under attack.
   • Backup: Acts as a safety net when resilience fails.

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Non-Repudiation

• Prevents users from denying their actions.
• Combines authentication and integrity to ensure:
  1. The identity of the user is authenticated.
  2. The integrity of the transaction is verified.

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Types of Attacks

1. Network-Based Attacks:
   • Target the network infrastructure.
   • Example: Denial of Service (DoS) attacks.
2. Host-Based Attacks:
   • Target specific devices like computers, mobiles, or laptops.
   • Examples: Ransomware, I Love You Virus.
3. Application-Based Attacks:
   • Target applications directly.
   • Example: SQL Injection.

• Impact on the CIA Triad:
  • Every attack affects at least one or more aspects of Confidentiality, Integrity, or Availability.

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Targets of Attacks

1. People: Individuals connected to an organization.
2. Process: Weaknesses in operational procedures.
3. Technology: Outdated or vulnerable systems (e.g., older versions of operating systems).

Acronyms to Remember:

• CIA: Confidentiality, Integrity, Availability
• PPT: People, Process, Technology
• NHA: Network, Host, Application

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Startup Services

• Startup Services: Services that start automatically when a machine boots.
• Safe Mode:
  • Starts with minimal services, bypassing startup programs.
  • Useful for identifying and preventing malicious files or viruses that auto-execute at boot.
• Use the start command in Windows to open default applications.

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Additional Tools and Resources

• iknowwhatyoudownload.com:
  • Tracks files downloaded via torrent using a public IP address.
• archive.org: Review how websites appeared in the past.

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