extensions

Problem

This is a really weird text file TXT? Can you find the flag?

• TXT File

Solution

1. A quick file type check with file reveals that we have a PNG file instead of a TXT file:

    file flag.txt
    flag.txt: PNG image data, 1697 x 608, 8-bit/color RGB, non-interlaced

2. Change the filename to flag.png and get the flag:

   

3. Katana can solve this challenge:

    Target completed in 7.29 seconds after 6105 unit cases
    tesseract(/data/targets/flag.txt) ➜
    picoCTF{now_you_know_about_extensions} - (copied)

Flag

picoCTF{now_you_know_about_extensions}