Nuclei
Category: Web Application Security
Language: Go
Type: Template-Based Scan
📘 Definition & Purpose
Nuclei is a highly customizable, template-based vulnerability scanner written in Go. It allows developers and hunters to write YAML templates that define HTTP/TCP/DNS/File requests and verify responses using string, hex, or regex matchers.
🧪 Core Mechanics
Nuclei sends rapid network requests based on templates stored in the community Nuclei templates repository. It matches responses against predefined signatures to check for vulnerabilities like exposed .git folders, SSRF, XSS, default panels, and critical CVEs.
🚀 Usage & Cheat Sheet
# Scan a list of hosts using all critical and high severity templates
nuclei -l live_web.txt -severity critical,high
# Target a specific vulnerability or CVE template
nuclei -u https://target.com -t cves/2021/CVE-2021-44228.yaml
# Scan for exposed panel files and configuration leaks
nuclei -u https://target.com -t exposures/
# Automatically update templates database
nuclei -update-templates
🔗 Integration
This tool is utilized across the: