SherpaCTF 2025 CTF Writeup

15 - Fifteen

Interact with a restricted terminal environment and extract the contents of the `flag.txt` file using limited command-line capabilities.

Fifteen - CTF Challenge Writeup

Challenge Information

Name: Fifteen
Category: Misc
Points: 10
Objective: Interact with a restricted terminal environment and extract the contents of the flag.txt file using limited command-line capabilities.

Solution

From User Fourteen, we’re dropped into a restricted terminal.
I’ve faced similar setups before, but didn’t take notes — so it took me around an hour of trial and error to rediscover the solution.
In restricted shells where typical tools or flags are disabled, breaking down output is key.
The command that worked: grep -o . flag.txt
This prints the flag character by character, bypassing common output restrictions and filters.

Flag

SHERPACTF25{EZPZ}