Phishing Prevention: Building a Multi-Layered Defence
Phishing remains the most common attack vector, involved in over 36% of data breaches according to Verizon's 2025 DBIR. Effective phishing defence requires multiple complementary layers, each reducing risk incrementally.
The Layered Approach
No single control stops all phishing. The most effective strategy combines technical controls with human awareness:
- Email Security Gateway (45% reduction) — blocks known malicious emails, suspicious attachments, and weaponised links before they reach inboxes
- Multi-Factor Authentication (45% reduction of remaining risk) — even when credentials are stolen, MFA prevents account compromise
- Security Awareness Training (40% reduction of remaining risk) — equips employees to identify and report sophisticated phishing that bypasses technical controls
Combined Effectiveness
Using a diminishing returns model, these three controls together reduce phishing risk by approximately 82%. The residual 18% represents sophisticated, targeted attacks that may require additional controls like DNS filtering, browser isolation, or managed detection.
Measuring Phishing Defence
Track phishing simulation click rates monthly to measure programme effectiveness. A decreasing trend validates your investment. Report rates — employees reporting suspicious emails — are equally important and indicate a healthy security culture.