Level 11

Login

SSH: ssh [email protected] -p 2220

Challenge URL: https://overthewire.org/wargames/bandit/bandit12.html

Task

The password for the next level is stored in the file data.txt, where all lowercase (a-z) and uppercase (A-Z) letters have been rotated by 13 positions.

Solution

Let's see the files present:

bandit11@bandit:~$ ls
data.txt
bandit11@bandit:~$ wc -l data.txt
1 data.txt
bandit11@bandit:~$ cat data.txt
Gur cnffjbeq vf TEBbmJCB8DlA0zTewHxVQ0JPLxMvDkeA

To rotate the characters use the tool tr. To rotate by 13 positions:

cat data.txt | tr 'a-z' 'n-za-m' | tr 'A-Z' 'N-ZA-M'

The first argument takes the input string format, the second takes the output format - if a is rotated by 13 positions it becomes n and goes till z, then starts over from a to m. The second pipe is for uppercase characters.
Both the cases can be combined in the same argument also, but it's difficult to understand.

One liner: cat data.txt | tr 'a-zA-Z' 'n-za-mN-ZA-M'