Hidden in Plain Sight

This is a sample write-up about a made-up challenge. Delete it once you have real write-ups.

Challenge

We are given cat.png and told “there is more to this cat than meets the eye”.

Solution

Start with the cheapest check: look for readable text inside the file.

strings cat.png | tail -n 3
# IEND
# U0FNUExFe3N0cjFuZ3NfZjFyc3R9

Something was appended after the end of the image data, and it looks like Base64:

echo 'U0FNUExFe3N0cjFuZ3NfZjFyc3R9' | base64 -d
# SAMPLE{str1ngs_f1rst}

What I learned

Run the simple tools first: file, strings and exiftool take seconds and solve a surprising number of easy forensics challenges.