PicoCTF Writeup – plumbing
# Information:
CTF Name: PicoCTF
CTF Challenge: plumbing
Challenge Category: General Skills
Challenge Points: 200
PicoCTF 2019.
# Challenge Description:
Sometimes you need to handle process data outside of a file. Can you find a way to keep the output from this program and search for the flag? Connect to jupiter.challenges.picoctf.org 4427.
Hint: Remember the flag format is picoCTF{XXXX}. What’s a pipe? No not that kind of pipe… This kind.
# Writeup
In this challenge, we are given an address and a port to connect. I immediately thought about using netcat to do so. I used the following command:
mregra on Cyber ~$ nc jupiter.challenges.picoctf.org 4427
The output was a huge amount of phrases that seemed random. It was clear to me that the flag was somewhere in the middle of all of that garbage. To filter it and find the flag easily, I decided to use the grep command and the pipe command combined with the netcat.
The final command was the following:
mregra on Cyber ~$ nc jupiter.challenges.picoctf.org 4427 | grep "pico"
This command sends the output from the nc command into the grep command through the pipe (|) and prints to the standard output all the lines that match the regex expression given, in this case, “pico”.
And the output was:
Thank you very much for reading!
Cheers,
MRegra
