DefendTheWeb.net, previously called HackThis.co.uk, is a very famous and well-known interactive security platform where you can learn and challenge your skills.. It contains challenges from several different cybersecurity fields.
I’ve decided to have a bit of fun and try to solve every single challenge presented, from the easiest to the hardest. (although easy and hard will be different depending on your skillset and field of expertise).
As I do with any challenge website, I WILL NEVER post the flag in cleartext, as it kills the fun and thrill of finding it, however I will post my way (or ways) of getting there. This is done in respect of the website’s security and non-disclosure policy, even when it doesn’t have one ;).
Challenge Crypt 5 / Crypt
This challenge is rated as Crypt, so it may or may not be a little tricky to solve. This time the author only gives us a description followed by a password field:
Decrypt the following text qoymlNlpY :ccdf lpy yzJ .qoh ln lxigqoh qlxlm eeiw zot ydpy gmipylnoC ,zot gmiyqdncyzo ho ydpy ci lniqk tN .lsie sooe tlpy ydpw yom ,smipy amd tdc tlpy ydpw tj lefolf gmigazb ho ydpy ci lniqk tN .tyicoiqzk ho ydpy ci lniqk tN .edminiqk d nd i clT
Again another challenge to decrypt a text, and it also looks like a substitution cipher but a bit different as we have some different characters like “.”, “:”. It may be a polyalphabetic cipher. The first thing I noticed was actually that we have only one “:” being used, and regarding DefendTheWeb.net, it is generally to show the password at the end of the sentence, so I think this sentence is reversed.
Using a simple “rev” command in shell, we can reverse the text:
$ echo "qoymlNlpY :ccdf lpy yzJ .qoh ln lxigqoh qlxlm eeiw zot ydpy gmipylnoC ,zot gmiyqdncyzo ho ydpy ci lniqk tN .lsie sooe tlpy ydpw yom ,smipy amd tdc tlpy ydpw tj lefolf gmigazb ho ydpy ci lniqk tN .tyicoiqzk ho ydpy ci lniqk tN .edminiqk d nd i clT" | rev
Tlc i dn d kqinimde. Nt kqinl ic ypdy oh kzqiociyt. Nt kqinl ic ypdy oh bzagimg flofel jt wpdy yplt cdt dma ypims, moy wpdy yplt eoos eisl. Nt kqinl ic ypdy oh ozycndqyimg toz, Conlypimg ypdy toz wiee mlxlq hoqgixl nl hoq. Jzy ypl fdcc: YplNlmyoqNow let’s try to pass this text through https://www.guballa.de/substitution-solver and there we have it a simple substitution cipher but reversed later on after encryption.
I hope you enjoyed this challenge. See you on the next one
