useless

Published: April 26, 2023Updated: December 9, 2025

Description

The “useless” workstation exposes SSH access plus a suspicious calculator script. Somewhere inside its documentation hides the flag.

SSH into saturn.picoctf.net on port 64713 with the provided credentials.

List the home directory, execute ./useless, and read both the script and its man page.

ssh picoplayer@saturn.picoctf.net -p 64713
password
ls && ./useless
man useless

Solution

  1. Step 1Inspect the script
    Running the script without proper arguments prompts you to “Read the code first.” View the bash source to learn it performs basic math operations.
    cat useless
  2. Step 2Read the manual
    The maintainer stashed the picoCTF flag at the bottom of the manual page. Simply run man useless and scroll to the end.
    man useless

Flag

picoCTF{us3l3s...it3d_4373}

No exploitation is required; just follow the hints inside the tool’s documentation.