Overview of ROYFEL Defense-in-Depth Architecture

This document outlines the technical security protocols implemented across the ROYFEL environment. The architecture adheres to a robust, layered security methodology, ensuring redundancy and minimal single points of failure. The strategy integrates controls at the network perimeter, core network gateway, and endpoint level to provide comprehensive protection against all known and emerging threat vectors.

Implementation Details: Tiered Defense

Tier 1: Network Perimeter Security (Firewall Level) - Primary Defense

Component: Core Network Firewall/Router Appliance | IOC Source: ROYFEL Premium Blocklist

Methodology: Stateless IP Filtering. The firewall performs rapid ingress and egress filtering based on IPv4 addresses and CIDR notations in the feed. This process is highly optimized for performance, stopping traffic before deep packet inspection is necessary.

Rationale: This efficiently addresses high-volume, commodity threats (botnets, scanners, C2 infrastructure) at wire speed, drastically reducing the attack surface and internal network noise. This layer ensures that endpoints are exposed only to necessary, standard internet traffic.

Tier 2: Network Gateway DNS Filtering (Core Router Level) - Secondary Defense

Component: Core Router configured with Cloudflare DoH

Methodology: Encrypted DNS Resolution and Threat Intelligence. All DNS queries are sent securely over HTTPS. Cloudflare’s enterprise threat intelligence validates requested domains against known malware distribution points, phishing sites, and C2 infrastructure, refusing to resolve malicious domains.

Rationale: This mitigates threats using fast-flux DNS or compromised servers. It is a critical defense against internet-based attacks even if the IP address has not yet been blocklisted in Tier 1. It adds a vital layer of domain reputation checking to our defense strategy.

Tier 3: Endpoint Protection (Client Device Level) - Final Defense

Component: Symantec Endpoint Protection (SEP) Unmanaged Client on Windows 11 IoT Enterprise LTSC 2024

Methodology: Multi-Engine EPP (Insight, SONAR AI, Traditional AV). The client operates autonomously, receiving updates via LiveUpdate. Its core engines include: Insight for global file reputation analysis, SONAR for highly aggressive, real-time behavioral heuristics watching for malicious intent, and traditional signature matching.

Rationale: The SONAR engine provides essential zero-day protection, catching threats based on malicious behavior even if they bypass Tiers 1 and 2. It is the core defense against novel malware execution on the host machine itself.

Conclusion and Robustness

The ROYFEL Architecture provides a superior security posture via a principle of defense-in-depth:

Redundancy: Failure of one layer (e.g., a new threat IP not yet on the Tier 1 list) is mitigated by subsequent layers (Tier 2 domain filtering, Tier 3 behavioral analysis).
Performance: The bulk of malicious traffic is stopped efficiently at the network edge, preserving endpoint performance.
Comprehensive Coverage: This system effectively protects against IOCs across all major types: IP addresses, domain names/URLs, and file behavior/hashes.
If a brand-new threat IP is not on your list in Layer 1, Layer 2 might block the domain name.
If a new IP and a new domain are both missed, Layer 3 (SEP’s SONAR engine) will stop the malicious behavior upon execution.

DISCLAIMER: This document describes an aggressive security posture. Any user replicating this architecture **must** implement appropriate whitelisting policies for essential network resources and IP addresses. Failure to do so will likely result in the blocking of legitimate internet access or internal network resources. The Security Operations Team or ROYFEL is not responsible for connectivity issues arising from improper configuration.