Bandit: Level 11→12

bandit level-11-12

The goal of this level is to get the password for the next level in a file called data.txt that has been encoded using Rot13

To accomplish this we are going to use the tr command to decode the data inside the file and retrieve the password

Rot13 is a simple letter substitution cipher (Caesar Cipher) that replaces a letter with the 13th letter after it in the alphabet.

First we need to log onto the level

Type the command ssh bandit11@bandit.labs.overthewire.org -p 2220
Enter the password IFukwKGsFW8MOq3IRFqrxE1hxTNEbUPR

When we do a quick search with the ls command we can see that the file named data.txt is located in the home directory

If we output the data using the cat command we get an output of a string that looks very similar to the password format however we can tell that is encoded with Rot13

To decode the Rot13 we need to use the tr command

Type the command cat data.txt | tr '[A-Za-z]' '[N-ZA-Mn-za-m]'

The Caesar Cipher shifts plaintext three letters to the left to create ciphertext.

In this case, tr ‘[A-Z]’ ‘[X-ZA-W]’, tr translates all occurrences of ‘A’ to ‘X’, ‘B’ to ‘Y’, ‘C’ to ‘Z’, ‘D’ to ‘A’, etc.

[X-ZA-W] just means that your output starts with the letter X and continues through the letter Z, then continues with the letter A through the letter W. You could also use [XYZABCDEFGHIJKLMNOPQRSTUVW] instead but tr understands the hyphen ‘-‘ to mean ‘through’.

When this command is run it outputs The password is 5Te8Y4drgCRfCx8ugdwuEX8KFC6k2EUu

Copy the password 5Te8Y4drgCRfCx8ugdwuEX8KFC6k2EUu
Type exit to logout

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