frncscrlnd's writeups

Writeups from challenges and CTFs i take part in.


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Level 11 → Level 12

After logging in with

ssh bandit11@bandit.labs.overthewire.org -p 2220

Password: dtR173fZKb0RRsDFSGsg2RWnpNVj3qRr

and running ls we can see that there is a data.txt file inside the /home/bandit11 directory. As the game tells us, this text file is ROT13 encoded, a type of encoding based on the Ceasar cipher that has a key value of 13. We’ll need to use tr to decode this string.

tr basically replaces characters in a text file by mapping characters from one charset to another (e.g. tr 'a-z' 'A-Z'turns the text to uppercase).

In our case:

tr 'A-Za-z' 'N-ZA-Mn-za-m' < data.txt

Where ‘A-Za-z’ is the first set of chars, ‘N-ZA-Mn-za-m’ is the second and data.txt is the source file.

this will print our password:

7x16WNeHIi5YkIhWsfFIqoognUTyj9Q4