07 - Resilience & Physical Security

Resiliency & Business Continuity

Asset Tracking: Inventory management (barcodes, RFID, asset tags); know what you have to protect it
Asset Protection: Anti-tamper, encryption at rest, secure transport, environmental controls (HVAC)
Configuration Management: Baseline hardening, version control, change management; prevents "drift" that breaks failover
Backups: Full (everything), Incremental (changes since last backup), Differential (changes since last full); Deduplication removes redundant blocks to save storage
Snapshots: Point-in-time copy of VM/disk; not a backup (same storage, corrupted if primary fails); fast rollback for patching errors
Instant Failover: Seamless cutover to secondary system; requires replication (synchronous for zero RPO)

Data Disposal

Physical: Shredding (paper), Degaussing (magnetic destruction), Pulverizing/Drilling (drives); Certificate of Destruction required for audit trail
Cryptographic: Crypto-shredding (destroy encryption keys rendering data unreadable); faster for cloud storage; ensure no key recovery possible

Disaster Recovery & Redundancy

Site Redundancy:
Hot: Live mirror; immediate failover (highest cost)
Warm: Partial equipment/data; hours to activate
Cold: Empty space/hardware; days to weeks (cheapest)
Clustering:
Active/Active: All nodes process load; fault tolerant but complex
Active/Passive: Standby takes over on failure; simpler but wasted standby capacity
Power: PDU (Power Distribution Unit—rack-level); UPS (Uninterruptible Power Supply—battery for graceful shutdown); Generator (long-term outage, diesel/propane)

Diversity & Deception

Vendor/App Diversity: Avoid single point of failure (e.g., split ISPs, multi-cloud); prevents supply chain monoculture
Deception Tech:
Honeypot: Single fake system to lure attackers
Honeynet: Entire fake network for advanced analysis
Honeyfile: Bait documents (fake salary.xlsx) that trigger alerts when opened
Fake Telemetry: Decoy credentials/logs to confuse adversaries
Resilience Testing: TTX (Tabletop Exercise—walk through scenarios/discussion-based); Failover Tests (actual live cutover to validate recovery time)

Physical Security Controls

Perimeter: Fencing (height/climb deterrent), Bollards (vehicle barriers), Barricades, Lighting (deterrent + CCTV aid), controlled Ingress/Egress points
Access Control: Mantrap/Vestibule (interlocking doors; prevents tailgating), Access Badges (proximity/smart cards with photo), Cable Locks (laptop/desktop anti-theft)
Surveillance: CCTV (deterrent + detective; retention policies), UAV/Drones (aerial perimeter monitoring or threat detection)
Colocation: Cages (physical separation in shared datacenter), Protected Cable Distribution (conduit to prevent tapping/interference)

Alarm Systems

Motion: PIR (Passive Infrared) sensors detect body heat
Noise: Glass-break detectors, vibration sensors
Duress: Panic buttons (silent alarm) for immediate response
Temperature: Environmental monitoring for server overheating; tied to HVAC/BMS

Quick Checks: Hot site = ready now; Warm = data there, needs spin-up; Cold = empty building. Snapshots ≠ Backups (same failure domain). Active/Active shares load; Active/Passive waits. Crypto-shredding beats physical destruction for speed but requires strong key management.