PicoCTF Writeup – what’s a net cat?

Information: 

CTF Name: PicoCTF

CTF Challenge: what’s a net cat?

Challenge Category: General Skills

Challenge Points: 100

PicoCTF 2019.

# Challenge Description: 

Using netcat (nc) is going to be pretty important. Can you connect to jupiter.challenges.picoctf.org at port 41120 to get the flag?

Relevant hint: nc tutorial

Writeup 

By looking at the hint and clicking on the word tutorial we are redirected to the netcat Linux manual page. 

The nc (or netcat) is used to open TCP connections, send UDP packets, listen to both UDP and TCP connections in the respective ports. It is also used for port scanning, among other things. 

Knowing this I decided to try to run the netcat command on my Linux terminal with the address and port given in the description.

The full command that I used: 

mregra on Cyber ~$ netcat jupiter.challenges.picoctf.org 41120

Note: It is also possible to use nc instead of netcat. 

Let’s try to better understand the command arguments. 

First, we give the address of the machine that we are trying to connect to, in this case, is “jupiter.challenges.picoctf.org”. 

Next, we provided the port on which this machine is listening, which is 41120.

As you can see we now have the flag:

Show flag
picoCTF{nEtCat_Mast3ry_3214be47}

The image source can be found here.    

Thank you very much for reading!

Cheers,

MRegra


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3 Replies to “PicoCTF Writeup – what’s a net cat?”

  1. Howdy, i read your blog from time to time and i own a similar one and i was just wondering if you get a lot
    of spam comments? If so how do you prevent it, any plugin or anything you can recommend?
    I get so much lately it’s driving me crazy so any assistance is very much appreciated.

    1. At the moment I have no solution for it.
      I am in fact facing a similar issue and I hope to find a solution, when I do I will write a post about it.
      Thanks for reading, have a nice day.
      Cheers,
      MRegra

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