<- IMAGINARYCTF

Secure

2 minutes to read

We are given this website (https://puzzler7.imaginaryctf.org:7002/):

Secure 1

Since the name of the challenge is “Secure” and the browser showed a warning telling that the certificate is self-signed, we must examine the certificate.

Flag

For instance, we can use curl with verbose(-v) and insecure (-k) modes. And there’s the flag, in the certificate’s subject and issuer:

$ curl -vk https://puzzler7.imaginaryctf.org:7002/
*   Trying 137.184.207.224:7002...
* Connected to puzzler7.imaginaryctf.org (137.184.207.224) port 7002 (#0)
* ALPN: offers h2
* ALPN: offers http/1.1
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.3 (IN), TLS handshake, Encrypted Extensions (8):
* TLSv1.3 (IN), TLS handshake, Certificate (11):
* TLSv1.3 (IN), TLS handshake, CERT verify (15):
* TLSv1.3 (IN), TLS handshake, Finished (20):
* TLSv1.3 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.3 (OUT), TLS handshake, Finished (20):
* SSL connection using TLSv1.3 / TLS_AES_256_GCM_SHA384
* ALPN: server did not agree on a protocol. Uses default.
* Server certificate:
*  subject: C=US; ST=California; L=ictf{securesecuresecuresecuresecuresecuresecuresecuresecure}; O=ImaginaryCTF  
*  start date: Nov  8 09:57:31 2022 GMT
*  expire date: Nov  8 09:57:31 2023 GMT
*  issuer: C=US; ST=California; L=ictf{securesecuresecuresecuresecuresecuresecuresecuresecure}; O=ImaginaryCTF
*  SSL certificate verify result: self signed certificate (18), continuing anyway.
> GET / HTTP/1.1
> Host: puzzler7.imaginaryctf.org:7002
> User-Agent: curl/7.86.0
> Accept: */*
>
* TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
* TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
* old SSL session ID is stale, removing
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Server: Werkzeug/2.1.2 Python/3.8.10
< Date: Fri, 16 Dec 2022 14:20:27 GMT
< Content-Type: text/html; charset=utf-8
< Content-Length: 6
< Connection: close
<
* Closing connection 0
* TLSv1.3 (OUT), TLS alert, close notify (256):
secure