1. Control Diversity
    1. When designing a secure network, diverse controls create a stronger security program.
  2. Control Diversity may take two forms:
    1. Control Type Diversity:
      1. Using controls from different categories to achieve the same control objective.
      2. (Reminder) Security Controls may be categorized as:
        1. Administrative (Operational)
        2. Physical
        3. Technical (Logical)
      3. Combining controls from two or more of these categories is more likely to successfully protect an organizations against a security threat.
      4. Example:
        1. Prevent data exfiltration by insiders (employees) of the organization
          1. Technical Controls:
          2. Data Loss Prevention (DLP) Systems
          3. Watch for and drop sensitive information sent outside the organization's network.
          4. Monitoring Controls
          5. Prevent Removable Storage Devices
          6. Content Filters
          7. Prevent Access to P2P and File Sharing Sites
          8. Administrative Controls:
          9. Background Checks of New Hires
          10. Non-Disclosure Agreements (NDA)
          11. Physical Controls:
          12. Security Guards with authority to perform random bag inspections
          13. Security cameras
    2. Vendor Diversity:
      1. Using products from different vendors to achieve the same control objective.
      2. Example:
        1. Our organization's firewall architecture is designed such that:
          1. One firewall is placed at the Internet (Customer) edge of our organization's network.
          2. A second firewall internal to our network protects the data center from the rest of the organization's network.
          3. Both firewalls protect the data center from the Internet.
        2. Single Vendor vs Multiple Vendors
          1. Advantage of Single Vendor:
          2. The IT Team only needs to manage one type of firewall. If a complex problem arises, your IT team understands and can contribute to solving that problem.
          3. Advantage of Multiple Vendors:
          4. A security flaw in a single firewall will not allow an attacker to gain access to a network segment protected by two firewalls from different vendors.