Over The Wire - Bandit - Level 25#

Level Goal#

A daemon is listening on port 30002 and will give you the password for bandit25 if given the password for bandit24 and a secret numeric 4-digit pincode. There is no way to retrieve the pincode except by going through all of the 10000 combinations, called brute-forcing. You do not need to create new connections each time

Commands you may need to solve this level#

Steps#

For this challenge, we are going to use ncat for the connection on port 30002 and a script to generate a text. The connection is pretty simple:

ncat localhost 30002

This connects to a waiting daemon where it expects the combination bandit24_password+pincode. But trying one by one will take an eternity. One good thing is that ncat can receive a textfile of inputs and process it normally. So, imagine that we have the following file list.txt:

password_bandit24 0
password_bandit24 1
password_bandit24 2
password_bandit24 3

If we input the file this way:

ncat localhost 30002 < .list.txt

Each line will be processed like a common input from the user. Well, ok, we just need to write 10000 lines like that. Also taking an eternity to do that. So we are going to create a shell script to do that for us. We are going to create a script called create_list.sh, make it executable with chmod +x create_list.sh and edit it with something like this:

for i in {0..10000}
do
echo "password_bandit24 $i" >> ./list.txt
done

Where:

for i in {0..10000} : is a loop that repeats from 0 to 10000, saving the current position in $i variable
echo "password_bandit24 $i" : print the string with the password+pincode from the variable
>> ./list.txt : add a new line into a file, in this case the list.txt file on each loop interaction

Run this script with ./create_list.sh and the file will have all the lines necessary to find the next password. Now to get the next password just run ncat with our filled list.

ncat localhost 30002 < .list.txt