This post is part of an ongoing practical bug bounty series.

If you haven't read them yet, start here:

This article focuses on one tool — not theory, not buzzwords — but how ffuf actually leads to real bugs when used correctly.

🧠 What ffuf Really Is (and What It Isn't)

Most people describe ffuf as:

"A fast web fuzzer"

That's true — but incomplete.

ffuf is an attack surface discovery engine. Used correctly, it helps you find:

  • Hidden endpoints
  • Forgotten APIs
  • Admin panels
  • IDOR candidates
  • 403-protected paths
  • Logic flaws, not just directories

Used incorrectly, it gives you:

  • Thousands of useless results
  • False positives
  • Burnout

Let's avoid that.

🛠️ Installation (Kali / Parrot)

ffuf is preinstalled on Kali. If not:

sudo apt update && sudo apt install ffuf -y

Check:

ffuf -h

🎯 Step 1: Smart Target Selection (Critical)

Do not run ffuf blindly.

Bad target:

https://target.com/

Good targets:

  • Discovered subdomains
  • API hosts
  • Admin or app-specific paths
  • Endpoints found via:
  • Burp
  • waymore
  • katana
  • historical URLs

Example:

https://api.target.com/FUZZ

📂 Step 2: Wordlists That Actually Matter

Avoid huge lists at first.

Recommended:

  • raft-small-words.txt
  • api-endpoints.txt
  • Custom lists built from:
  • JavaScript files
  • Historical URLs
  • Burp proxy history

Example:

ffuf -u https://api.target.com/FUZZ \
-w raft-small-words.txt \
-mc 200,204,301,302,401,403

🔍 Step 3: Filtering Noise (This Is Where Pros Win)

Most beginners stop here. Don't.

Use filters aggressively:

-fs 0
-fl 10
-fw 50

Example:

ffuf -u https://target.com/FUZZ \
-w common.txt \
-fs 4242

You're not looking for many results. You're looking for different results.

🚪 Step 4: ffuf → 403 Bypass Discovery

403 responses are gold, not dead ends.

ffuf -u https://target.com/FUZZ \
-w common.txt \
-mc 403

Now test bypass techniques manually or scripted:

  • /admin/.
  • /admin;
  • /admin/%2e
  • Header tricks:
  • X-Forwarded-For: 127.0.0.1
  • X-Original-URL

This is where real findings start.

🔗 Step 5: ffuf → Burp Suite (Clean Handoff)

Anything interesting goes into Burp, not automation.

Workflow:

  1. Send endpoint to Repeater
  2. Change:
  • HTTP methods
  • User IDs
  • Object references
  1. Observe:
  • Access control issues
  • IDOR patterns
  • Role-based failures

ffuf finds the door. Burp tells you what's behind it.

🧪 Real-World Bugs Found With ffuf

Things I've personally seen (and reported):

  • /api/admin/users → IDOR
  • /internal/export → data leakage
  • /v2/backup → full database download
  • /admin/health → internal metadata
  • 403 → bypass → privilege escalation

None of these came from "spray and pray".

❌ Common ffuf Mistakes (Avoid These)

  • Running massive wordlists immediately
  • Ignoring response size
  • Treating ffuf results as findings
  • Not chaining into Burp
  • Not understanding the application logic

ffuf is discovery, not exploitation.

🧠 Where ffuf Fits in a Real Workflow

Recon → httpx → ffuf → Burp → IDOR / Access Control → Impact

It's a bridge, not a destination.

🏁 Final Thoughts

If you learn one tool deeply, ffuf is a perfect choice.

Not because it's fast — but because it forces you to think about:

  • Application structure
  • Logic
  • Access control
  • Impact

That's what bug bounty rewards.

👏 If this helped you, please clap — it really helps the post reach more readers.

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