Fehu

The Elder Weapon

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Fehu is a high-performance security toolkit for offensive security professionals and AI-powered automation. Multiple scanning capabilities in a single, fast binary.

Etymology

Fehu (ᚠ) is the first rune of the Elder Futhark alphabet, symbolizing wealth, abundance, and power.

Features

Module	Description
xss	XSS scanner with smart adaptive mode - context-aware, reflection analysis
sqli	SQL Injection scanner (error, boolean, time-based)
dirscan	Directory fuzzer with built-in 400+ paths, smart 404 detection
portscan	Port scanner with built-in top-100/top-1000 profiles
subdomain	Subdomain enumeration with built-in 200+ subdomains
headers	Security headers analyzer
fetch-proxies	Download free proxies for evasion

Key Capabilities:

• Smart XSS Mode: Probes character/tag filters, constructs working payloads adaptively
• Proxy Rotation: Built-in proxy rotation with free proxy fetching
• User-Agent Rotation: Randomized browser fingerprints
• Zero External Dependencies: Built-in wordlists for directories, subdomains, ports, SQLi, XSS
• Smart 404 Detection: Filters soft-404 pages automatically
• AI-Friendly: --json flag outputs structured JSON for LLM parsing
• Blazing Fast: Async I/O with configurable concurrency
• Single Binary: All tools in one compiled executable

Installation

git clone https://github.com/svviitzerland/fehu.git
cd fehu
cargo build --release

Usage

XSS Scanner

# Smart mode - adaptive probing (recommended)
fehu xss --url "http://target.com/search?q=test" --smart

# Context-aware mode
fehu xss --url "http://target.com/search?q=test"

# Deep scan + WAF bypass
fehu xss --url "http://target.com/search?q=test" --smart --deep

Evasion Features (Global Flags)

# Use proxy
fehu dirscan --url "http://target.com" --proxy http://127.0.0.1:8080

# Random User-Agent
fehu sqli --url "http://target.com/page?id=1" --random-agent

# Fetch and use free proxies
fehu dirscan --url "http://target.com" --fetch-proxies

# Add delay between requests
fehu xss --url "http://target.com/search?q=test" --smart --delay 500

# Download proxies for later use
fehu fetch-proxies -o proxies.txt

Directory Scanner (Built-in Wordlist)

# Uses built-in wordlist (400+ paths)
fehu dirscan --url "http://target.com"

# With file extensions
fehu dirscan --url "http://target.com" -x php,asp,html

# Custom wordlist (optional)
fehu dirscan --url "http://target.com" -w /path/to/wordlist.txt

Port Scanner (Built-in Profiles)

# Uses top-1000 ports (default)
fehu portscan --host "target.com"

# Top 100 ports (faster)
fehu portscan --host "target.com" --ports top100

# Full scan
fehu portscan --host "target.com" --ports 1-65535 --threads 2000

Subdomain Enumeration (Built-in Wordlist)

fehu subdomain --domain "target.com"

SQL Injection Scanner

fehu sqli --url "http://target.com/page?id=1"

Security Headers Check

fehu headers --url "http://target.com"

JSON Output (AI Integration)

All modules support --json for structured output:

{
  "tool": "xss",
  "target": "http://example.com/search?q=test",
  "findings": [
    {
      "type": "smart_xss",
      "target": "http://example.com/search?q=test",
      "details": { "parameter": "q", "payload": "<img src=x onerror=alert(1)>", "method": "smart_adaptive" },
      "confidence": "high"
    }
  ],
  "status": "completed"
}

Examples

See the examples/ directory for detailed usage guides:

• XSS Scanning
• SQL Injection
• Directory Scanning
• Port Scanning
• Subdomain Enumeration
• Security Headers
• AI Integration
• Evasion Features

License

MIT License