Emmel

Points: 1222 [2000]

Description

Investigators have found a curious login page on a server belonging to COViD. Can you get past the login screen?

Login Page

Solution

The approach to this challenge was to create a picture that was most similar to the image being stored on the server.

Initially we uploaded quite a few pictures but did not manage to obtain more than 50%.

Hence, we wrote a script to brute force all rgb for a single pixel however that did not work as well.

As such we wrote a script that bruteforces rgb for a 4 pixels and that manage to work.

Submitting 40.jpg gave us the flag govtech-csg{I_L0V3_G00D_D0GG0S!}

from requests import post
from PIL import Image
color =[]

for i in range(0,256):
    img = Image.new('RGB',(2,2),color=(0,0,0))
    img.putpixel((0,0),(255,43,0))
    img.putpixel((0,1),(17,2,2))
    img.putpixel((1,0),(1,i,0))
    img.save("{}.jpg".format(i))
    files = {'file': open('{}.jpg'.format(i),'rb')}
    url = "http://yhi8bpzolrog3yw17fe0wlwrnwllnhic.alttablabs.sg:40751/recognize"
    r = post(url, files=files)
    reg = re.findall(r"Similarity: (.*)%", r.text)
    if reg:
        val = float(reg[0])
        color.append((val,i))
    else:
        print(r.text)
        print(i)
        break;  
color.sort(reverse=True)
print(color[:5])

Fun fact

After obtaining the flag we saw the floating dogos. Apparently that picture if converted to jpg could also solve the challenge LMAO Try it yourself! It’s in dogos.jpg

Flag

govtech-csg{I_L0V3_G00D_D0GG0S!}