Master Hidden Within The Slides

Challenge details

description

Solution

Opening up the attached PowerPoint file showed that there are 4 slides in total, nothing much. I even tried to move the images and texts around to see if there were something hiding beneath them.

Since the challenge title mentioned "master", I recalled that there's something known as "slide master" in PowerPoint. A quick search led us to the answer. Clicked on the first link.

The Microsoft documentation has detailed instructions on how to access the slide master.

Inspecting through every slide, we've found a weird string among one of them, which indeed looks like a base64 encoded string.

Throw that into CyberChef and we'll get the flag.

In the case that you have no idea what encoding it uses, you can try your luck by pasting it into CyberChef. Sometimes, a magic wand might appear and if you click on it, the site will automatically solve it for you.

Flag

GCTF{Sl1d3sss_M4staaaaaaa}