Network Defense Strategies

50 min

Zero Trust Architecture

"Never Trust, Always Verify" — Zero Trust eliminates the concept of a trusted internal network. Every access request is authenticated, authorized, and continuously validated regardless of location.

ZERO TRUST PRINCIPLES
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1. VERIFY EXPLICITLY    Authenticate every user, device,
                        and application; every time
2. LEAST PRIVILEGE      Minimum access required for tasks
                        Just-In-Time (JIT) access
3. ASSUME BREACH        Segment networks; limit blast radius
                        Monitor all traffic
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Key Technologies: MFA, PAM, Microsegmentation,
                  ZTNA, SASE, Continuous Monitoring

Network Segmentation

Dividing a network into isolated segments to contain breaches and reduce attack surface:

VLANs — Virtual segmentation at Layer 2; separate HR, Finance, IT, Guest
Microsegmentation — Granular isolation at the workload level (SDN)
Air-gapping — Complete physical isolation; used for critical infrastructure

Security Monitoring & SOAR

Security Orchestration, Automation and Response (SOAR) enables automated response to threats:

Automatically isolate infected endpoints
Block malicious IPs at firewall
Create incident tickets in ServiceNow
Notify security team via Slack/email

Threat Intelligence

Actionable intelligence about current and emerging threats, enabling proactive defense:

STIX/TAXII — Structured Threat Information eXpression format & sharing protocol
IOCs — Indicators of Compromise (malicious IPs, domains, file hashes)
Threat Feeds — VirusTotal, AlienVault OTX, MISP, Mandiant
MITRE ATT&CK — Map observed behaviors to attacker techniques