niteCTF 2025 writeup

Despite the time limit i had i did several challenges in this ctf and i will walk you through the intresting osint challenge,hope you enjoy and read to the end,or just skeem but leave a reaction at the end it helps me alot in creating the content.Lets get into it…

Challenge.

cornfield chase osint challenge description

On this challenge this is how i did it ,first of all we were given the link to the 360 image to locate the osint image.,…

osint challenge on cornfield chase

and there we were we got it the image ,

so lets put our detective skills to the test.

As usual i did a screenshot of the image and did a reverse image search but got nothing.

Sometimes, in OSINT (Open Source Intelligence) challenges, the smallest detail can blow a case wide open.

In this CTF challenge , the entire investigation began in a strange spot: a corn/rice field if it suits what you see. I couldn’t move — just look around. And then I saw it: a single electric pole with a small metal plaque.

the electricity pole

Step 1 — Recognizing the System

The plaque belonged to a Taiwanese electric pole. Taiwan Power Company has a grid algorithm — a systematic way to label every utility pole in the country so that workers can locate them quickly, even with nothing but pen and paper.

The whole algorithm you can read it here https://wiki.osgeo.org/wiki/Taiwan_Power_Company_grid

the system used in taiwanese grids

According to my pole number thats **N0489** this is what in short it means

N refers to the large 80×50 km block labeled “N”

It sits below M, left of O, **above Q ,**So the first thing N0489 tells you is

Inside block N the the area is subdivided into 1 km × 1 km squares and numbered sequentially.

Taipower numbering convention:

First two digits (04) → east–west index.

Last two digits (89) → north–south index

so:

N 04 89

│ │ └─ northing index

│ └──── easting index

└────── main grid block

This gives you a specific 1 km square inside block N.

Step 2 — Narrowing It Down With a Second Code

And my code from the pole here its BE61 And for this we use the same system but diffrent grid thats this

the second grid

for this grid it divides the area into:

Horizontal (A–H)
Vertical (A–E)

Here, B (horizontal) and E (vertical) narrowed the location even further. The number 61 could allow for even finer precision.

And then this whole math we did and there is automatic tool to automate that all work and just pinpoint the location so lets do that because we have learned something from that whole math and numbers

Step 3 - Automating the rest

found this tool online big up to the creator .https://0d.lv/toolbox/taipower

Just entered the full code from the Taiwanese utility pole we have— that is K2812CB64—and it instantly pinpointed the exact pole on a map.,that was very cool and easy.

the coordinates