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Pico CTF - Nice Netcat

· One min read
Marios Daskalas
Marios Daskalas
Cyber Security Specialist

Run the following command.

nc mercury.picoctf.net 35652

returns an output of numbers in decimal format. We have to create a python script in order to convert from this decimal output to ASCII text.

First save the output to a file named flag.txt

nc mercury.picoctf.net 35652 > flag.txt

Pico CTF - Moneyware

· One min read
Marios Daskalas
Marios Daskalas
Cyber Security Specialist

We need to find the malware name for a bitcoin address. Bitcoin address is the following.

1Mz7153HMuxXTuR2R1t78mGSdzaAtNbBWX

Just search for 1Mz7153HMuxXTuR2R1t78mGSdzaAtNbBWX malware and you will be able to find the flag. Here is a hint...

picoCTF[P...a]

Pico CTF - Magikarp Ground Mission

· 3 min read
Marios Daskalas
Marios Daskalas
Cyber Security Specialist

In this ctf, we will learn about SSH, ls and cat. If you know nothing about these terms, do not worry, we will cover them right now.

You can always use the following commands to learn more about them in the terminal.

man ssh
man ls

In a short, ssh is a program that has the purpose of logging into a remote machine and executes commands that the user wants.

Pico CTF - Hashing Job App

· One min read
Marios Daskalas
Marios Daskalas
Cyber Security Specialist

First, open up the terminal and using the following command initiate a connection with the server.

nc saturn.picoctf.net 57689

You have to md5 hash the presented text between quotes. To do that, you can apply this command.

echo -n "cholesterol" | md5sum

Pico CTF - Glitch Cat

· One min read
Marios Daskalas
Marios Daskalas
Cyber Security Specialist

Open up the terminal and type the following command.

nc saturn.picoctf.net 51109

You will get an output. Copy that output and open up a terminal and type the following command.

python3
print('picoCTF{gl17ch_m3_n07_' + chr(0x62) + chr(0x64) + chr(0x61) + chr(0x36) + chr(0x38) + chr(0x66) + chr(0x37) + chr(0x35) + '}')

Pico CTF - Fix Me 2

· 2 min read
Marios Daskalas
Marios Daskalas
Cyber Security Specialist

Download the fixme2.py file, open it in an editor and change it to the following.

import random

def str_xor(secret, key):
    #extend key to secret length
    new_key = key
    i = 0
    while len(new_key) < len(secret):
        new_key = new_key + key[i]
        i = (i + 1) % len(key)        
    return "".join([chr(ord(secret_c) ^ ord(new_key_c)) for (secret_c,new_key_c) in zip(secret,new_key)])

flag_enc = chr(0x15) + chr(0x07) + chr(0x08) + chr(0x06) + chr(0x27) + chr(0x21) + chr(0x23) + chr(0x15) + chr(0x58) + chr(0x18) + chr(0x11) + chr(0x41) + chr(0x09) + chr(0x5f) + chr(0x1f) + chr(0x10) + chr(0x3b) + chr(0x1b) + chr(0x55) + chr(0x1a) + chr(0x34) + chr(0x5d) + chr(0x51) + chr(0x40) + chr(0x54) + chr(0x09) + chr(0x05) + chr(0x04) + chr(0x57) + chr(0x1b) + chr(0x11) + chr(0x31) + chr(0x0e) + chr(0x51) + chr(0x5c) + chr(0x44) + chr(0x51) + chr(0x0a) + chr(0x5b) + chr(0x5a) + chr(0x19)

flag = str_xor(flag_enc, 'enkidu')

# Check that flag is not empty
if flag == "":
  print('String XOR encountered a problem, quitting.')
else:
  print('That is correct! Here\'s your flag: ' + flag)

Pico CTF - Fix Me 1

· 2 min read
Marios Daskalas
Marios Daskalas
Cyber Security Specialist

Download the fixme1.py file, open it in an editor and change it to the following.

import random

def str_xor(secret, key):
    #extend key to secret length
    new_key = key
    i = 0
    while len(new_key) < len(secret):
        new_key = new_key + key[i]
        i = (i + 1) % len(key)        
    return "".join([chr(ord(secret_c) ^ ord(new_key_c)) for (secret_c,new_key_c) in zip(secret,new_key)])

flag_enc = chr(0x15) + chr(0x07) + chr(0x08) + chr(0x06) + chr(0x27) + chr(0x21) + chr(0x23) + chr(0x15) + chr(0x5a) + chr(0x07) + chr(0x00) + chr(0x46) + chr(0x0b) + chr(0x1a) + chr(0x5a) + chr(0x1d) + chr(0x1d) + chr(0x2a) + chr(0x06) + chr(0x1c) + chr(0x5a) + chr(0x5c) + chr(0x55) + chr(0x40) + chr(0x3a) + chr(0x5f) + chr(0x53) + chr(0x5b) + chr(0x57) + chr(0x41) + chr(0x57) + chr(0x08) + chr(0x5c) + chr(0x14)
  
flag = str_xor(flag_enc, 'enkidu')
print('That is correct! Here\'s your flag: ' + flag)

Pico CTF - First Grep

· One min read
Marios Daskalas
Marios Daskalas
Cyber Security Specialist

First, download the file. Then navigate to the destination of the file and in terminal type the following command.

grep 'picoCTF' file

The command grep 'picoCTF' just searches through the file and prints the string that contains picoCTF.