Category: misc
Solver: MarDN, linaScience
Flag: GPNCTF{We're no strangers to loveYou know the rules and so do IA full commitment's what I'm thinking ofYou wouldn't get this from any other guyI just wanna tell you how I'm feelingGotta make you understandNever gonna give you upNever gonna let you downNever gonna turn around and desert youNever gonna make you cryNever gonna say goodbyeNever gonna tell a lie and hurt youWe've known each other for so longYour heart's been achingBut you're too shy to say itInside we both know what's been going onWe know the game and we're gonna play itAnd if you ask me how I'm feelingDon't tell me you're too blind to seeNever gonna give you upNever gonna let you downNever gonna turn around and desert youNever gonna make you cryNever gonna say goodbyeNever gonna tell a lie and hurt youNever gonna give you upNever gonna let you downNever gonna turn around and desert youNever gonna make you cryNever gonna say goodbyeNever gonna tell a lie and hurt youOoh (give you up)Ooh (give you up)Never gonna give, never gonna give (ooh, give you up)Never gonna give, never gonna give (ooh, give you up)We've known each other for so longYour heart's been achingBut you're too shy to say itInside we both know what's been going onWe know the game and we're gonna play itI just wanna tell you how I'm feelingGotta make you understandNever gonna give you upNever gonna let you downNever gonna turn around and desert youNever gonna make you cryNever gonna say goodbyeNever gonna tell a lie and hurt youNever gonna give you upNever gonna let you downNever gonna turn around and desert youNever gonna make you cryNever gonna say goodbyeNever gonna tell a lie and hurt youNever gonna give you upNever gonna let you downNever gonna turn around and desert youNever gonna make you cryNever gonna say goodbyeNever gonna tell a lie and hurt you}
Writeup
The challenge first appeared under a different title and description, and without a category tag. It was called “You know the GPNCTF{<text>} and so do I” and the description was given as “Never gonna give you newlines”, but it was changed to something way more helpful about six hours into the contest.
Confused guesses
Since this challenge was also labelled as “insanity check” and did not have a tag in the beginning, we immediately tried to think out of the box. The <text> tag in the title made us look through many pages of source code for the CTF’s website and the hint towards missing newlines made us think of streams and checking out the GPN live streams in the process. However, (aside from trying GPNCTF{dQw4w9WgXcQ}) we didn’t pay any particular attention to Rick Astley in particular, because so many challenged were themed after his song.
Less confused guesses
With the new description though, finding the solution was very easy. The link leads to the lyrics of Rick Astley’s famous song “Never gonna give you up”. The challenge title instructed us to put the full text without newlines between the flag markers, so we did exactly that. For the correct flag, we just copied the version of the lyrics from the given link and removed all newlines.