HACKvent 2015: Day 5

Challenge

You are given the following file:

Solution

So we open the PDF file to find 1 QR image in a ball. We scan it and we get the text Oooops !.

We then use an online tool to extract all images from the PDF (link). I do this because PDF files store all image files, even if they are completely overlapped by other images.

We then find 3 different images:

As it turns out, the QR image square was overlapping the other QR image in the ball. So we simply scan the QR image in the ball and get the flag.

Flag:

HV15-bkPb-tPEM-Fh3n-wvOi-5ZgD