Project Sekai - ✅-forensics-q10

Project Sekai

🔒 BYUCTF 2023 / ✅-forensics-q10

Q10 - 500 points

Category: Forensics Description: Wrap the flag in byuctf{}. The flag is case insensitive. Files:

https://cyberjousting.com/files/7a500581a24cb7754473c60f1fa4b3f5/file.png?token=eyJ1c2VyX2lkIjoyMjAsInRlYW1faWQiOjkxLCJmaWxlX2lkIjo1OH0.ZGerag.HskCVY-R0pylZON-DEeq-aiqI7c

Tags: Hard, Steg

Sutx pinned a message to this channel. 05/19/2023 10:01 AM

@Violin wants to collaborate

@Legoclones wants to collaborate

@afterworld wants to collaborate

https://apps.apple.com/us/app/q10-classic-crossword-game/id1116140771 q10 game

Image attachment

17:00

theres "Steg" tag so its prob image steg

17:00

wild guess is some places of the image have special marks and they are at exact position of a character, concatenating them gives flag

I don't want steg tag to be misleading, it's "steg" as in hidden message, not traditional image steg

17:01

afaik

o

I didn't actually solve this one lol

ic

17:01

so its like decoding chal then, not really steg

yeah

o ok

17:19

Image attachment

17:19

u r supposed to fill in the missing letters or smth?

17:19

this makes no sense tho cuz its kinda random msg (edited)

no its rows and cols crossword

17:20

idk if you need to fill those

17:20

its ave and yurt

o

17:22

wtf

@Sheep wants to collaborate

its scrabble

23:14

Image attachment

23:14

you start from the center, and you earn points based on the complexity of the word you fill in

oh

it could be something to do with the amount of points you get per word?

23:15

just a shot in the dark

15x15

23:16

ok start with middle A

the game is played between 2 ppl i think? and i think there are 26 turns in the board now where each round has 2 turns

23:30

1 point – A E I O U L N S T R 2 points – D G 3 points – B C M P 4 points – F H V W Y 5 points – K 8 points – J X 10 points – Q Z

23:30

there're also some dl dw tl tw

23:32

and also different online games have different dl dw tl tw for some reason

Sheep

Click to see attachment 🖼️

using this

23:33

krona gives 14 pts

also note that different squares on the board add different word/letter point multipliers

23:37

Image attachment

yeah

23:38

dl dw tl tw

23:38

the rule is a bit complicated

23:38

when adding scores

23:38

https://users.cs.northwestern.edu/~robby/uc-courses/22001-2008-winter/scrabble.html was reading this

23:38

need a simulator to calculate scores

ok lol

23:38

the problem im seeing

23:39

is that we dont know for sure what order these words were played in

the order should reflect encoded message

23:39

so we can get all possibilities

ah

first play is krona i think

23:40

then either ghostly or eternise

23:40

maybe score map to character if its guaranteed <26

23:40

not sure

23:40

i just have issue calculating scores

23:41

e.g. eternise will cross 2 double-word, how its calculated

23:42

there's bingo 50pts for using 7 letters so it cant be eternise

Image attachment

hmm

23:42

second move must be using up all tiles

23:42

lol

23:42

either of them

hm

23:45

so

23:45

even without the bingo

23:45

eternise being on two double word scores is 32

23:46

so we're not getting a clean character map

yeah not sure if we are supposed to calculate score if thats the case

yeah :l

@Legoclones any sanity check for this? are we meant to calculate score or sth, and is title relevant?

q10 seems like a scrabble term

23:52

OH

yeah its a game

q is worth 10 points

23:52

in game

23:52

because its hard to use

23:52

hm

there's only 1 Q here

23:53

ah

23:53

so it means we need to do sth with score?

no idea -.-

@4n0nym4u5 wants to collaborate

mkay its 3 am, im gonna turn in

23:56

gn

same

23:56

gonna check back later

23:57

we need a sanity check if its related with calculating scores

23:57

then its good to continue

23:57

might wait for @Legoclones to respond

sahuang

might wait for @Legoclones to respond

title is relevant, you've made a good first step connecting to scrabble

Legoclones

title is relevant, you've made a good first step connecting to scrabble

relevant as in q is worth 10 points (pointing to scrabble) or more to it?

pointing to scrabble

@rubiya wants to collaborate

@kanon wants to collaborate

btw i think it's useless but i counted occurrence of letters, only "EITTC" are unused (total 98 characters but 93 are used in the image)

10:20

doesnt form flag though so its prob sth else

@Guesslemonger wants to collaborate

summary:

title and attachment hints to scrabble only (15x15, start in middle A)
we are not sure if score calculation is needed
only unused letters are EITTC

why does it start in middle A ?

12:12

ok nvm

12:12

haven't played it

same, i just read rules

12:14

there're also DL DW TL TW for point multiplications

12:14

but we figured it will be hard to know the order of play, so it seems score calculation isnt intended

just calculate scores based on words only? nothing complicated

score depends on order

12:15

if you put a word besides a word and they form 2 words you get sum of their scores

i mean treat each word as individual word

and DL DW etc. can only be used once

12:15

hmm

it was solved in 8 minutes btw

12:16

so

i see

go as per gutenberg diagram

yeah i also think its not too realistic if we need to consider turns and stuff

12:17

so if its score related, 2 possibilities, count or not count the point multiplications

AVE = 6 YURT = 7

12:19

and so on

you counted 2x 3x or not?

Sheep

eternise being on two double word scores is 32

.

no idea, i am just using an online calculator

if chal hints to scrabble then it must be score related imo

so we want to superimpose a scrabble board also?

idk, just trying random things

12:22

prob gonna open a ticket and ask if its on right track doing score related calculations

12:22

a sec

12:26

i think one problem is there are 20+ words, what can we do after calculated scores or even map to chars

12:26

rearrange order of that many chars?

12:27

crazy that its solved in 8 mins

yeah idk what to do with scores, it's all over the place

12:31

no way to know the order

ye

12:36

im asking if score calculation is on right track

12:36

only after we know this can we proceed

12:37

honestly it would prob be a "click" if done in 8 min, like very easy decoding etc.

dont think he can tell lol

12:45

but doesnt matter ig, just gonna wait for solution

Yeah gg

12:48

2nd team just 3 challs behind lol

they need to max though

12:49

the 3 chals are CRC, pyjail, Lost

12:50

Lost is very easy i did in 10 min

12:50

but pyjail is not easy to get

12:50

idk crc, super guessy for me

12:50

but since they solved the steg one they can prob get it

yeah pyjail will be hard for them

@unpickled admin bot wants to collaborate

12:57

@jayden wants to collaborate

@hfz wants to collaborate

@Deleted User wants to collaborate

this is crazy btw

Image attachment

1

34 seconds apart

yeah interesting, on the hard chal with no solve for a day

big coincidence

no other weird overlapping solves that I can tell

yeah doesnt matter anyway lmao

Sheep

used /ctf solve

✅ Challenge solved.

daaaaaang

@Sheep

damn wtf nice

sheep orz

xD

18:48

what a game

18:48

maxed out >:P

Image attachment

damn wtf @Sheep W

19:00

what was solve @Sheep ?

had to pull out the family scrabble board lmao

Image attachment

19:06

7 remaining letters unused, which spelled out "ciphertext" in the lower right hand corner

19:06

super guess xD

mans pulled out an actual scrabble board orz

Sheep

7 remaining letters unused, which spelled out "ciphertext" in the lower right hand corner

i did that

19:23

why

sahuang

summary:

title and attachment hints to scrabble only (15x15, start in middle A)
we are not sure if score calculation is needed
only unused letters are EITTC

wtf

19:23

i only got eittc unused

19:24

oh

19:24

HER is there

19:24

and 2 spaces

19:24

lmfaoooo

19:24

@Sheep nice guess on last step

19:25

i didnt know i need to put that in bottom right, super guessy

Sheep

had to pull out the family scrabble board lmao

orz

how the fuck ppl connect remaining "e i t t c space space" with "putting in bottom right"

19:27

insane

I don't think bottom right matters

19:28

I think that's just where he was organizing the extra leftover letters

19:28

didn't realize there was no p or x tho that's weird

19:28

are spaces wildcards in scrabble or something?

Legoclones

I think that's just where he was organizing the extra leftover letters

this is huge guessy

19:28

the remaining 5 letters dont get a proper word

19:28

and you need to add 3 characters and fill in the 2 missing letters

Legoclones

are spaces wildcards in scrabble or something?

kind of

19:29

empty tiles

ahh

sahuang

how the fuck ppl connect remaining "e i t t c space space" with "putting in bottom right"

yeah,, and its gets an insane amount of points

19:30

thats why it caught my eye :)

19:30

it lands on two triple spaces

19:30

so 9x points

ahh

plus bingo, so +50

thats why

19:30

i see

19:30

i didnt connect the last bits for scores

yeah, really guessy lol

i even asked author if "eittc" remained are useful but he didnt tell xd

¯\_(ツ)_/¯

19:31

odd chall

19:31

kinda weird in a ctf tbh

19:32

more of a word problem than anything

yeah

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