Zeek – Network Security Monitor

Zeek (formerly Bro) is a powerful open-source network security monitor that provides deep inspection of network traffic. Unlike signature-based IDS systems, Zeek transforms network traffic into high-level logs and events, enabling comprehensive security monitoring, forensics, and network analysis. It is widely used in enterprise environments, research institutions, and security operations centers.

Key Features

• Protocol Analysis – Deep inspection of HTTP, DNS, SSL, SSH, and 50+ protocols
• Structured Logs – Detailed, searchable logs of all network activity
• Scripting Language – Custom detection and response capabilities
• File Extraction – Carve files from network traffic
• Intelligence Framework – Integrate threat intelligence feeds
• Cluster Support – Scale across multiple systems

Installation

# Debian/Ubuntu
sudo apt install zeek

# Using official repository
echo "deb http://download.opensuse.org/repositories/security:/zeek/xUbuntu_22.04/ /" | sudo tee /etc/apt/sources.list.d/zeek.list
sudo apt update && sudo apt install zeek

# RHEL/CentOS
sudo dnf install zeek

# From source
git clone --recursive https://github.com/zeek/zeek
cd zeek && ./configure && make && sudo make install

Common Usage

# Analyze pcap file
zeek -r capture.pcap

# Live capture on interface
sudo zeek -i eth0

# Run with specific scripts
zeek -r capture.pcap script.zeek

# Deploy as cluster
zeekctl deploy

# Check cluster status
zeekctl status

# View generated logs
cat conn.log | zeek-cut id.orig_h id.resp_h service

Log Types

Zeek generates structured logs including conn.log (connections), dns.log (DNS queries), http.log (HTTP requests), ssl.log (TLS connections), files.log (file transfers), and many protocol-specific logs.

Use Cases

Zeek excels at security monitoring, incident response, network forensics, threat hunting, compliance auditing, and integrating with SIEM platforms.

Download Zeek