VPNs, IDS & IPS: Network Security Defense Systems

Enterprise VPN Types:

• IPsec VPN: Network-layer encryption (IKEv2)
• SSL VPN: Application-layer access (TLS 1.3)
• WireGuard: Modern lightweight alternative

Security Best Practices:

• Multi-factor authentication for all VPN connections
• Split tunneling disabled for sensitive access
• Always-on VPN for remote devices

Case Study:

After the 2020 SolarWinds breach, Microsoft shifted to certificate-based VPN authentication

Detection Methods:

• Signature-based: Known attack patterns
• Anomaly-based: Behavioral deviations
• Heuristic: Algorithmic threat scoring

Enterprise Solutions:

# Suricata rule example
alert tcp $EXTERNAL_NET any -> $HOME_NET 445 \
(msg:"ET EXPLOIT Possible EternalBlue"; \
flow:established,to_server; \
content:"|FF|SMB|2 00 00 00 00|"; depth:5; \
reference:cve,2017-0144; sid:2024444; rev:2;)
        

Deployment Tip:

Place IDS sensors at network egress points and between security zones

Prevention Techniques:

• Packet dropping: Block malicious traffic flows
• TCP resets: Terminate suspicious connections
• Threat intelligence feeds: Real-time blocklists

Configuration Guidelines:

• Start in monitoring mode before enabling blocking
• Create exceptions for encrypted traffic inspection
• Test rules with vulnerability scanning tools

Vendor Comparison:

Cisco Firepower vs Palo Alto vs CheckPoint IPS throughput benchmarks

Enterprise Deployment Model:

1. VPN concentrator for remote access (IPsec/SSL)
2. Network IPS at internet gateway
3. Host-based IDS on critical servers
4. Cloud IDS for SaaS protection

Security Orchestration:

# Example SIEM correlation rule
WHEN VPN login AFTER HOURS
AND unusual geo-location
AND subsequent IDS alert
THEN severity=critical
        

Zero Trust Alternative:

ZTNA replacing traditional VPNs with app-level micro-tunnels