HCSC 2025 - The Silent Terminal

Description

Deep within an abandoned server network, a secret terminal lies hidden, accessible only to those who know the right key. However, amidst the signals flowing through the network, someone has carelessly left behind a small piece of information that could grant access. The secret the system tried to conceal is now out in the open for all to see, but only the observant ones will find it.

Password for the ZIP archive: hcsc2025

10.10.1-9.12:9239

SHA1: ad4bbf5e40af8bda394cd8ac8310899d844db1c7
SHA256: 60de2de13933d978cdc36137ee2f91589053856902250bbde8c887ed2e77e13d

Metadata

• Filename: ctf-the_silent_terminal.zip
• Tags: wireshark, telnet
• Points: 100
• Number of solvers: 116

Solution

We got a network capture file which we can open in Wireshark.

If we follow the TCP streams, tcp.stream eq 32 will give us a telnet session where we can see the plaintext credentials: john / CUReatOP

Now we can use nc to access the service and get the flag.

$ nc 10.10.4.12 9239
Enter username: john
Enter password: CUReatOP
HCSC{Pl41n_T3xT_Tr4nSf3r_1s_R1sKy}

The flag is: HCSC{Pl41n_T3xT_Tr4nSf3r_1s_R1sKy}