Broken Website - web

Summary

The future is quic, this challenge was not.

Problem

curl -v https://broken-website.tamuctf.cybr.club/

* Host broken-website.tamuctf.cybr.club:443 was resolved.
* IPv6: (none)
* IPv4: 54.91.191.64
*   Trying 54.91.191.64:443...
* connect to 54.91.191.64 port 443 from 192.168.0.79 port 53398 failed: Die Wartezeit für die Verbindung ist abgelaufen
* Failed to connect to broken-website.tamuctf.cybr.club port 443 after 133017 ms: Could not connect to server
* closing connection #0
curl: (28) Failed to connect to broken-website.tamuctf.cybr.club port 443 after 133017 ms: Could not connect to server

Every attempt to connect to this site fails and/or times out.

Solution

Steps to solve:

Check some ports
Check ALL the ports
even try udp, because when there is no tcp, there is only udp left. But why would someone within their right mind use udp to serve a website!?
try port knocking
- with default sequences
- with custom sequences
  - consider doing a rain dance
absolutely NO response from the server, so it HAS to be a network problem
- with 3 persons:
  - blame AWS, because there currently is a offcially announced AWS problem between USA and europe
    - find out that when connecting via nordvpn there is an answer on port 80
    - rent servers in different parts of the world to check network issue
  - blame challenge autor
  - blame ctf infrastructure
  - complain in support discord
- loop for 3 hours
ignore this messed up stuff
- go to a concert
- drink some wine
come back, think about tcp and udp
- vaguely remember some vague reference some month ago when someone mentioned quic

Try quic/http3

https://curl.se/docs/manpage.html#--http3-only curl -v --http3-only https://broken-website.tamuctf.cybr.club/

* Host broken-website.tamuctf.cybr.club:443 was resolved.
* IPv6: (none)
* IPv4: 54.91.191.64
*   Trying 54.91.191.64:443...
* SSL Trust Anchors:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
* SSL connection using TLSv1.3 / TLS_AES_128_GCM_SHA256 / X25519MLKEM768 / id-ecPublicKey
* Server certificate:
*   subject: 
*   start date: Mar 22 07:09:30 2026 GMT
*   expire date: Mar 22 19:09:30 2026 GMT
*   issuer: CN=Caddy Local Authority - ECC Intermediate
*   Certificate level 0: Public key type EC/prime256v1 (256/128 Bits/secBits), signed using ecdsa-with-SHA256
*   Certificate level 1: Public key type EC/prime256v1 (256/128 Bits/secBits), signed using ecdsa-with-SHA256
*   subjectAltName: "broken-website.tamuctf.cybr.club" matches cert's "broken-website.tamuctf.cybr.club"
* OpenSSL verify result: 14
* SSL certificate OpenSSL verify result: unable to get local issuer certificate (20)
* QUIC connect to 54.91.191.64 port 443 failed: SSL peer certificate or SSH remote key was not OK
* Failed to connect to broken-website.tamuctf.cybr.club port 443 after 117 ms: SSL peer certificate or SSH remote key was not OK
* closing connection #0
curl: (60) Failed to connect to broken-website.tamuctf.cybr.club port 443 after 117 ms: SSL peer certificate or SSH remote key was not OK
More details here: https://curl.se/docs/sslcerts.html

curl failed to verify the legitimacy of the server and therefore could not
establish a secure connection to it. To learn more about this situation and
how to fix it, please visit the webpage mentioned above.

Certificate problem? -> ignore https://curl.se/docs/manpage.html#--insecure curl --http3-only --insecure https://broken-website.tamuctf.cybr.club/

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Fancy Website</title>
    <link rel="stylesheet" type="text/css" href="style.css">
    <link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link href="https://fonts.googleapis.com/css2?family=Ubuntu:ital,wght@0,300;0,400;0,500;0,700;1,300;1,400;1,500;1,700&display=swap" rel="stylesheet">
</head>
<body>
    <h1>Welcome to my website!</h1>
    <h2>Here's the flag:</h2>
    <h2>gigem{7h3_fu7u23_15_qu1c_64d1f5}</h2>
</body>
</html>

Flag

gigem{7h3_fu7u23_15_qu1c_64d1f5}

4.2 KiB Raw Blame History