Writeup Age of Aquarius - UIUCTF 2025

Introduction

This was an OSINT challenge in which we had knowledge of a person's Tumblr account and, based only on that account, we needed to find their state/province and country. You can check the account here.

Solution

By scrolling through the person's Tumblr, we can easily find a birth chart and a post saying the person's birthday is 07/12/2004. With this, I used AI to interpret the astrological data contained in the image together with the birthday date.

Based on the analysis of these data, the AI was able to narrow down the possible birth locations to compatible time zones and latitudes, with Canada and the United States being the best hypotheses, as they present compatible time zones with the birth chart.

Knowing that the flag format was uiuctf{country,state/province} or uiuctf{country,none}, it was sufficient to simply bruteforce all the valid combinations, since there are 50 states in the US and 13 provinces/territories in Canada, less than 100 possibilities.

In less than 10 minutes we got the flag: uiuctf{canada, saskatchewan}