Network Security Monitoring

🔥 Vibe Prompt

"Set up network monitoring: Zeek (Bro), Suricata, and Security Onion."

Zeek (formerly Bro)

# Install
sudo apt install zeek

# Config: /opt/zeek/etc/node.cfg
[zeek]
type = standalone
interface = eth0

# Default scripts cover:
# - HTTP, DNS, SSL, SMTP, SSH, FTP
# - Conn.log (all connections)
# - Files (extracted via HTTP, SMTP)

# Run
zeekctl deploy

Zeek Log Analysis

# Top talkers (by connection count)
cat conn.log | zeek-cut id.orig_h | sort | uniq -c | sort -nr | head -10

# Detect scanning
cat conn.log | zeek-cut id.orig_h id.resp_p proto | \
  awk '$3 ~ /tcp/' | cut -d' ' -f1 | sort | uniq -c | \
  awk '$1 > 100' | sort -rn

# SSL certificate anomalies
cat ssl.log | zeek-cut server_name cert_subject | \
  grep -v "Let's Encrypt" | grep -v "CloudFlare"

Suricata IDS/IPS

# Install and configure
sudo apt install suricata

# Download Emerging Threats rules
sudo suricata-update update-source oisf
sudo suricata-update

# Run
sudo suricata -c /etc/suricata/suricata.yaml -i eth0

# Check alerts
tail -f /var/log/suricata/fast.log
# 05/15/2024-14:32:10.123456  [**] [1:2024210:3] ET EXPLOIT Apache Log4j RCE [**]

Security Onion (Full Platform)

# Boot ISO → follow wizard
# Automatically sets up:
# - Zeek (network logs)
# - Suricata (IDS alerts)
# - Elasticsearch + Kibana (visualization)
# - TheHive (incident management)
# - Playbooks (automated response)

sos-admin status
# Shows all running services

Key Metrics to Monitor

| Metric | Tool | Alert | |--------|------|-------| | New connections/sec | Zeek | >10000/s | | DNS queries (unique) | Zeek | >1000/min | | TLS certificate age | Zeek | <30 days | | IDS alerts | Suricata | Any | | Scan detection | Zeek | >100 ports/host | | DNS tunneling | Zeek | High entropy domains |

SIEM Integration

Zeek + Suricata → Logstash → Elasticsearch → Kibana (ELK)
                                            ↓
                                     Security Analyst

Network Security Course Complete! 🎉

✅ Network Segmentation
✅ Firewall & IDS/IPS
✅ VPN & Remote Access
✅ DDoS Protection
✅ Monitoring

Key Points

Understand the core concepts thoroughly
Practice with hands-on code examples
Apply knowledge to real-world problems
Review and reinforce through exercises

Further Learning

Official documentation
Open source projects on GitHub
Community forums and discussions
Related courses and tutorials

網路監控：看不見的安全威脅

攻擊者可能已經在你的網路內部——你需要監控工具來發現異常行為。

監控工具

| 工具 | 功能 | |:----|:----| | Wireshark | 封包層級分析 | | Zeek（Bro） | 網路流量分析框架 | | Snort/Suricata | 入侵偵測系統（IDS） | | ELK Stack | 日誌分析與視覺化 |

課程總結

這堂網路安全課從基礎概念、防火牆/IDS、VPN、WAF 到監控——你現在可以設計一個多層防禦的企業網路架構。