generating palindromes with John the Ripper

Question

How can I configure John the Ripper to generate only mangled (Jumbo) palindromes from a word-list to crack a password hash? (I've googled it but only found "how to avoid palindromes")

Answer 1

in john/john.conf (for e.g. 9 and 10 letter palindromes) -append the following rules at the end:

# End of john.conf file.
# Keep this comment, and blank line above it, to make sure a john-local.conf
# that does not end with \n is properly loaded.
[List.Rules:palindromes]
f
f D5

then run john with your wordlist plus the newly created "palindromes" rules:

$ john --wordlist=wordlist.lst --rules:palindromes hashfile.hash 

rule f simply appends a reflection of itself to the current word from the wordlist, e.g. P4ss! -> P4ss!!ss4P

rule f D5 not only reflects the word but then deletes the 5th character, e.g. P4ss! -> P4ss!ss4P

I haven't found a way to "delete the middle character" so as of now, the rule has to be adjusted to the required length of palindromes, e.g. f D4 for length of 7, f D6 for length of 11 etc.

Edit: Possible solution for variable length (not tested yet):

f
Mr[6

M = Memorize current word, r = Reverse the entire word , [ = Delete first character, 6 = Prepend the word saved to memory to current word

With this approach the palindromes could additionally be "turned inside out" (word from wordlist at the end of the resulting palindrome instead of at beginning)

f   
Mr[6
Mr]4

M = Memorize current word, r = Reverse the entire word , ] = Delete last character, 4 = Append the word saved to memory to current word