Ubuntor - 55 (Recon)
Write-up by GenericNickname
Find out about me.
It's all about me!
Figure out the flag based on the information Ubuntor has given.
Both the description and the hint emphasize the word about, so I instantly decided it must be related to the about page of the competition. I also googled Ubuntor, which brought up the github of Samuel Kim. Sure enough, on the about page, Samuel Kim's profile picture on the about page looks like a QR code, but the entire thing can't be seen.
Viewing the image will give you the full QRCode:
Decoding the QR code gives some base64 text, which can be decoded using python. Looking at the base64 reveals that the base64 encoded text is actually the bytes of a png file, so saving it as one gets this image:
Unfortuantely, this doesn't work as the flag, so there is more work to do. Downloading the original QR code and looking at it in either a hex editor or notepad++ reveals flag.txt towards the bottom of the file. This suggests that the image also contains a zip file, so changing the extension to .zip and opening it in a program such as 7zip will show flag.txt as its contents.
Trying to open flag.txt promopts the user for a password, and the first thing I tried was the message from the PNG we found earlier:
BE SURE TO DRINK YOUR OVALTINE!. This opens flag.txt and gives the flag.