Performing Network Traffic Analysis with Zeek

Overview

Zeek (formerly Bro) is an open-source network analysis framework that operates as a passive network security monitor. Unlike traditional signature-based IDS tools, Zeek generates high-fidelity structured logs from observed network traffic, capturing detailed metadata for protocols including HTTP, DNS, TLS, SSH, SMTP, FTP, and dozens more. Zeek's extensible scripting language enables custom detection logic, behavioral analysis, and automated response. This skill covers deploying Zeek, understanding its log architecture, writing custom detection scripts, and integrating outputs with SIEM platforms.

When to Use

• When conducting security assessments that involve performing network traffic analysis with zeek
• When following incident response procedures for related security events
• When performing scheduled security testing or auditing activities
• When validating security controls through hands-on testing

Prerequisites

• Linux server (Ubuntu 22.04+ or CentOS 8+) with 4+ CPU cores and 8GB+ RAM
• Network TAP or SPAN port mirroring configured for traffic capture
• Zeek 6.0+ installed (via package manager or source compilation)