Weird

50 Points / 356 Solves
Overall difficulty for me (From 1-10 stars): ★☆☆☆☆☆☆☆☆☆

Background

This file was supposed to contain a secret message but it looks like just a blank page. Something weird is going on here.

Find the flag

In this challenge, we can download a file:

┌[siunam♥earth]-(~/ctf/RITSEC-CTF-2023/Steganography/Weird)-[2023.04.02|19:23:17(HKT)]
└> file blank.png      
blank.png: PNG image data, 600 x 600, 8-bit/color RGBA, non-interlaced

It’s a PNG image file.

First, we can try to read it’s metadata via exiftool:

┌[siunam♥earth]-(~/ctf/RITSEC-CTF-2023/Steganography/Weird)-[2023.04.02|19:23:23(HKT)]
└> exiftool blank.png  
ExifTool Version Number         : 12.57
File Name                       : blank.png
[...]

However, nothing interesting.

Then, I decided to upload that image to aperisolve.fr, which is an online tool to solve steganography challenge:

Boom! We found the flag!

Flag: RS{Th4t5_w4cky_m4n}

Conclusion

What we’ve learned:

Viewing Image With Separate Color