CTFlearn-Writeups/Programming/The Adventures of Boris Ivanov Part 2

The Adventures of Boris Ivanov Part 2

The main idea finding the flag using OpenCV library and Python.

Step-1:

After we download confetti.zip, we see that we have 500 photos.

Each dimension is 500 $\times$ 1 and according to problem statement, the image size is 500 $\times$ 500.

Step-2:

So basically, we have to concatenate the 500 images in vertical fashion.

Step-3:

Make a directory to extract all 500 images and set your pwd to that directory containing all images.

After that only work is to join all images.

Step-5:

I executed this simple Concatenate.py script and it worked.

from PIL import Image

listimages=[]
for i in range(0,500):
    listimages.append(Image.open(str(i) + ".png"))  # Make a list of pointers to the 500 pictures.

concatenate=Image.new("RGB",(500,500))              # Size of the concatenate picture
Y_offset=0

for i in listimages:
    concatenate.paste(i,(0,Y_offset))
    Y_offset+=1                                     # Add 1 at a time , Because the height of each picture is 1.
concatenate.save("concatenate.png")

Step-6:

We get the output as concatenate.png after the above script is run. The image is as follows:

We see a hex code in between.

Step-7:

The Hex code is as follows: 66 6c 61 67 7b 74 68 33 5f 4b 47 42 5f 6c 30 76 33 73 5f 43 54 46 7d

I converted it to text online to get the flag.

Step-7:

Finally the flag becomes: flag{th3_KGB_l0v3s_CTF}