picoCTF 2019 What Lies Within Writeup

What Lies Within is a forensics puzzle worth 150 points.

The description of this puzzle:

There's something in the building. Can you retrieve the flag?

An image buildings.png is provided, which shows a picture of a building:

buildings.png

First, I tried using exiftool and just looking around at the picture. This is likely a steganography challenge based on it being in the Forensics category and the puzzle being an image. Usually for steganography challenges, I start by simply trying a bunch of known decoders against it.

In this instance, I got a hit with zsteg:

Solved with zsteg.

I should really sit down one day and make a list of decoders and what kinds of files they work on, and script something out to automate these easier challenges.

One thought on “picoCTF 2019 What Lies Within Writeup

  1. Pingback: picoCTF Writeups – DMFR SECURITY

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s