picoCTF - Extensions

• URL: https://play.picoctf.org/practice/challenge/52
• Title: Extensions
• Tags: Medium, Forensics, picoCTF 2019
• Author: Sanjay C/Danny
• Started: 19 July 2025
• Solved: 19 July 2025
• Description:

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

After downloading the text file, I checked the integrity using file command

strikingsoul@ramones:~/Downloads$ file flag.txt 
flag.txt: PNG image data, 1697 x 608, 8-bit/color RGB, non-interlaced

It was actually a picture file

After renaming, I finally got the flag

The flag is picoCTF{now_you_know_about_extensions}