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Write-ups for TCTT2022/Network/02

Flag pattern

TCTT2022{xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx}

Challenge Files

network-challenge02

Solution

First, Let open the pcap file with wireshark and analyze it with Statistics > Protocol Hierarchy.

It look like there is a lot of Telnet request, so filter it with Right Click > Apply as Filter > Selected.

We sort the results by length.

Then, we follow the TCP stream of the longest one.

And that is the TCP stream no.20128, which looks like SSH connection.

We can see that, they are doing something with secret.zip

Let go to the next stream and you can see that the stream is starting with PK which is the signature of zip file.

If you want to save the zip file, you can do it by changing the stream to raw data and save it as zip file.

We got secret.zip file but it has password.

Let crack it with fcrackzip and rockyou wordlist with this command.

fcrackzip -u -D -p <PATH-TO-WORDLIST> <PATH-TO-ZIP-FILE>

As you can see, the password is P@ssw0rd.

We use previous password to unzip the zip file and we got secret.

We cat that file, and the result is tctt2022{Welcome_R00t_T3ln3t}