• Security Perimeter:
  • Definition: The first line of defense that separates a trusted internal network from an untrusted external network.
  • Components:
    • Firewalls: Control incoming and outgoing network traffic based on predetermined security rules.
    • Routers: Direct traffic between networks, often with filtering capabilities to block unauthorized access.
    • Proxies: Act as intermediaries for requests from clients seeking resources from other servers, providing anonymity and additional security.
    • IDS (Intrusion Detection Systems): Monitors network traffic for suspicious activity and alerts administrators of potential threats.
    • IPS (Intrusion Prevention Systems): Not only detects but also prevents identified threats from reaching the network.
• Zero Day:
  • Context: Refers to vulnerabilities that are exploited before the vendor is aware of them and can patch the software.
  • Mitigation: Application whitelisting can help prevent zero-day attacks by allowing only approved applications to run, reducing the risk of executing malicious code.

The security perimeter is crucial for defending against external threats, while practices like application whitelisting help safeguard against newly discovered vulnerabilities.