═══════════════════════════════════════════════════════════════════════════════ 🚨 TROUBLESHOOTING GUIDE - No Webhook Response ═══════════════════════════════════════════════════════════════════════════════ Challenge: https://pasteboard-1fb68b7836775bea.chals.uoftctf.org/ Webhook: https://webhook.site/d8111fd3-599a-47ab-bcab-94d5ec54e078 ═══════════════════════════════════════════════════════════════════════════════ 📋 STEP-BY-STEP VERIFICATION ═══════════════════════════════════════════════════════════════════════════════ STEP 1: Create the Paste ───────────────────────────────────────────────────────────────────────────── 1. Go to: https://pasteboard-1fb68b7836775bea.chals.uoftctf.org/note/new 2. Leave "Title" field empty (or enter anything) 3. Paste PAYLOAD 1 (below) into the "Body" field 4. Click "Create Note" 5. You'll be redirected to a URL like: https://pasteboard-1fb68b7836775bea.chals.uoftctf.org/note/XXXXXXXX 6. COPY THIS FULL URL STEP 2: Report to Bot ───────────────────────────────────────────────────────────────────────────── 1. Go to: https://pasteboard-1fb68b7836775bea.chals.uoftctf.org/report 2. Paste the FULL note URL from step 1 3. Click Submit 4. You should see "Queued" message STEP 3: Wait and Check ───────────────────────────────────────────────────────────────────────────── 1. Keep your webhook tab open: https://webhook.site/d8111fd3-599a-47ab-bcab-94d5ec54e078 2. Wait 5-10 seconds (bot visits within 30 seconds) 3. Webhook should receive a request ═══════════════════════════════════════════════════════════════════════════════ 🧪 TEST PAYLOADS - Try in This Order ═══════════════════════════════════════════════════════════════════════════════ PAYLOAD 1: ULTRA-SIMPLE (Start Here!) ─────────────────────────────────────────────────────────────────────────────
✅ If webhook receives ?ping=1 → XSS is working! Try more complex payloads ❌ If no response → Something is wrong with the basic setup PAYLOAD 2: Multiple Pings ─────────────────────────────────────────────────────────────────────────────
→ Sends 3 requests (step=1, step=2, step=3) → Tests if timing matters PAYLOAD 3: Comprehensive Data Dump ─────────────────────────────────────────────────────────────────────────────
→ Sends ALL available data as POST → Check webhook POST body for cookie, localStorage, window properties PAYLOAD 4: Delayed Cookie Check ─────────────────────────────────────────────────────────────────────────────
→ Waits 5 seconds before checking → Maybe flag is set asynchronously PAYLOAD 5: Image + Fetch (Dual Method) ─────────────────────────────────────────────────────────────────────────────
→ Uses both Image and fetch() → At least one should work ═══════════════════════════════════════════════════════════════════════════════ ❓ COMMON ISSUES & SOLUTIONS ═══════════════════════════════════════════════════════════════════════════════ ISSUE: No webhook response at all ───────────────────────────────────────────────────────────────────────────── ✓ Did you paste the payload in the BODY field (not title)? ✓ Did you report the NOTE URL (not the /report URL)? ✅ Correct: https://pasteboard-.../note/abc123 ❌ Wrong: https://pasteboard-.../report ✓ Is your webhook still open/active? ✓ Did you wait 30 seconds? ISSUE: "Failed to fetch" or CORS errors ───────────────────────────────────────────────────────────────────────────── → CSP allows connect-src *, so this shouldn't happen → Try PAYLOAD 5 (Image method) ISSUE: XSS works but no flag found ───────────────────────────────────────────────────────────────────────────── → Try chrome:// navigation payloads (see ALTERNATIVE_PAYLOADS.py) → The flag might require CDP access (advanced) → Check if cookie appears after delay (PAYLOAD 4) ═══════════════════════════════════════════════════════════════════════════════ 🎯 NEXT STEPS AFTER CONFIRMING XSS WORKS ═══════════════════════════════════════════════════════════════════════════════ 1. Once PAYLOAD 1 works, you know XSS is executing 2. Try PAYLOAD 3 to see what data is available 3. If still no flag, the challenge likely needs: - Chrome DevTools Protocol access (CDP) - Navigation to chrome:// URLs - Or the flag is set differently than expected 4. Run these Python scripts for advanced payloads: python ALTERNATIVE_PAYLOADS.py python CDP_MASTER_GUIDE.py ═══════════════════════════════════════════════════════════════════════════════ 💡 REMEMBER ═══════════════════════════════════════════════════════════════════════════════ The XSS vulnerability is REAL and WORKING (you've tested it locally). If webhook gets NOTHING, it's likely: 1. Paste wasn't created correctly 2. Wrong URL was reported to bot 3. Bot didn't visit (rare) 4. Webhook closed/expired Start with PAYLOAD 1 - if that works, everything else will follow! ═══════════════════════════════════════════════════════════════════════════════