BASIC COMS

Proof of flag 

FLAG = ctf{ca314be22457497e81a08fc3bfdbdcd3e0e443c41b5ce9802517b2161aa5e993}

Summary of the vulnerabilities identified

Looking for http requests captured by Wireshark in the given file we find only 4 request, one of which contains our flag as a GET parameter.

Proof of solving

Based on the challenge description and title, we know we are supposed to be looking for a “basic” protocol in the pcapng file. One of the most basic protocols available is http and we in Wireshark we can filter to look only at the http requests and responses. Since there are only 4 requests made and the fact that there is a somewhat encoded message which says “The content of the flag is” we can guess that

“ca314be22457497e81a08fc3bfdbdcd3e0e443c41b5ce9802517b2161aa5e993” is indeed our flag.