Challenge Name: 1597

Detailed solution

Starting by cloning the repository

git clone http://git.ritsec.club:7000/1597.git/

ls -la                                                                 
total 8
drwxr-xr-x  3 kali kali 100 Apr 11 14:35 .
drwxr-xr-x 16 kali kali 540 Apr 11 14:35 ..
-rw-r--r--  1 kali kali   1 Apr 11 14:35 flag.txt
drwxr-xr-x  8 kali kali 260 Apr 11 14:35 .git
-rw-r--r--  1 kali kali  44 Apr 11 14:35 README.md

flag.txt is empty and README.md has the text A git challenge series? Sounds fun.

Let's check the.git folder

ls -la
total 20
drwxr-xr-x  8 kali kali 260 Apr 12 17:01 .
drwxr-xr-x  3 kali kali 100 Apr 12 17:01 ..
drwxr-xr-x  2 kali kali  40 Apr 12 17:01 branches
-rw-r--r--  1 kali kali 262 Apr 12 17:01 config
-rw-r--r--  1 kali kali  73 Apr 12 17:01 description
-rw-r--r--  1 kali kali  23 Apr 12 17:01 HEAD
drwxr-xr-x  2 kali kali 300 Apr 12 17:01 hooks
-rw-r--r--  1 kali kali 209 Apr 12 17:01 index
drwxr-xr-x  2 kali kali  60 Apr 12 17:01 info
drwxr-xr-x  3 kali kali  80 Apr 12 17:01 logs
drwxr-xr-x 15 kali kali 300 Apr 12 17:01 objects
-rw-r--r--  1 kali kali 181 Apr 12 17:01 packed-refs
drwxr-xr-x  5 kali kali 100 Apr 12 17:01 refs

Let's check the log of git commits

We can see an old text in the flag.txt

Your princess is in another castle

Let's check the packed-refs

cat packed-refs
# pack-refs with: peeled fully-peeled sorted
b123f674a07eaf5914eda8845d86b5219fc1de11 refs/remotes/origin/!flag
dcc402050827e92dbcf2578e24f2cba76f34229c refs/remotes/origin/master

Let's check the origin/!flag

Flag

RS{git_is_just_a_tre3_with_lots_of_branches}

Original writeup (https://github.com/BaadMaro/CTF/blob/main/RITSEC-CTF-2021/1597).