Alsavoudomila

Secrets picoCTF Writeup

author:

rudy_candy

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Description

We have several pages hidden. Can you find the one with the flag?

Additional details will be available after launching your challenge instance.

📝 Challenge Overview
Visit a web service running on a nonstandard port and explore URL paths to find nested hidden pages. By following links (or guessing common directory names) you eventually find a deeply nested page that contains the flag in its HTML. Note: the service may drop the connection intermittently, so be prepared for timeouts.

🔎 Step 1: Open the base URL in your browser

  1. Open your browser and go to:
    http://saturn.picoctf.net:61481/
  2. Inspect the page and elements—there is a link or element pointing to /secret. Click or navigate to that path.

📝 Explanation: Start with the root URL. Many CTF web challenges hide additional paths linked from the main page. Browsers render HTML and show links that lead to hidden directories.

🧭 Step 2: Follow the discovered path to /secret

  1. Navigate to: http://saturn.picoctf.net:61481/secret
  2. The /secret page reveals (or links to) another hidden path named /hidden. Move to that path.

📝 Explanation: Web challenges often nest secrets in multiple directories. Manually following links or reading the page source (right‑click → View Page Source) can reveal next-step paths.

🕵️ Step 3: Continue to /hidden and then /superhidden

  1. Visit: http://saturn.picoctf.net:61481/secret/hidden/
  2. From there, follow or guess the next path: http://saturn.picoctf.net:61481/secret/hidden/superhidden/
  3. The superhidden page contains the flag in its HTML content.

📝 Explanation: Sequentially exploring nested URLs uncovers deeper hidden pages. If links aren’t visible, try viewing the HTML, or use directory enumeration tools to discover common names.

⚠️ Note about reliability

  • The challenge host may drop the port or the service may become temporarily unavailable while you are exploring. If the site becomes unreachable, try again after a short wait or use command‑line tools that can retry (see tips).

📝 Explanation: CTF hosts running many challenges sometimes restart services or throttle connections. Expect transient failures and plan retries.

🏁 Capture the Flag
🎉 The flag found in the HTML of the superhidden page is:
picoCTF{succ3ss_@h3n1c@10n_39849bcf}

📊 Summary

StepCommand / ActionPurposeKey Result
1Open http://saturn.picoctf.net:61481/ in browserStart exploration of siteFound link/element to /secret
2Navigate to /secretFollow discovered pathFound link/element to /hidden
3Navigate to /secret/hidden/superhidden/Reach deeply nested pageFlag present in HTML: picoCTF{...}

💡 Beginner Tips

  • 🔎 Use View Page Source (right‑click) to see hidden links or comments that are not visible on the page.
  • 🧰 If the site goes down, retry after a short wait. Consider using curl -I or curl to check availability quickly from the terminal.
  • 🧭 Try manual navigation first; if that fails, use automated directory enumeration tools (e.g., gobuster, dirb) with a small wordlist to find common hidden folders.
  • 🛡️ Be polite — don’t flood the service with aggressive scans on a shared CTF host.

🎓 What you learn (takeaways)

  • Many web CTFs hide flags behind nested URLs—careful manual exploration often finds them.
  • Viewing the HTML source can reveal links, comments, or hints that aren’t rendered.
  • Services on nonstandard ports may be unreliable; expect intermittent downtime and plan retries.
  • Directory brute‑forcing is a useful fallback when links are not present in page source.

⚡ Short explanations for commands / techniques used

  • 🔗 Open URL in browser
    • What: Use a web browser to request the page.
    • Why: The browser renders HTML and exposes links and visible content.
    • Example: Enter http://saturn.picoctf.net:61481/ into the address bar.
  • 🧾 View Page Source / Inspect Element
    • What: Show raw HTML and DOM elements.
    • Why: Hidden links or comments may be present only in the HTML source.
    • How: Right‑click → View Page Source, or open Developer Tools (F12).
  • 🧭 Manual directory traversal
    • What: Type or click URLs to navigate to subpaths (e.g., /secret/hidden/superhidden/).
    • Why: Many flags are placed in nested directories; manual traversal is quick and simple.
  • 🐚 curl to check availability
    • What: Command‑line HTTP client to fetch pages or headers.
    • Why: Fast check for site up/down, useful when browser fails.
    • Example: curl -I http://saturn.picoctf.net:61481/secret (fetches headers).
  • 🧰 Directory enumeration tools (optional)
    • What: Tools like gobuster or dirb scan for common directory names.
    • Why: Automated discovery when links or hints are missing.
    • Caution: Use gentle settings on shared CTF hosts to avoid causing outages.

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