misc/Spice Harvest Data Recovery

51 solves / 454 points

Writeup by Aryan

The challenge originally prompts you to download a spreadsheet called spice_analysis.csv. When you open this spreadsheet, some data appears to be corrupted.

How the spreadsheet originally looks upon downloading it

My first thought was to clean all the data by taking a look at the corrupted columns and deleting the out-of-place characters and then replacing the semicolons with colons, mapping them to the original data format. Maybe the Group _ letters might spell out something special? However, when scrolling through the sheet, I saw an interesting entry.

Look at Row 107!

The data was clearly hex, and plugging it into CyberChef provided the following message: LOOK TO ONE OF EARTH'S GREATEST RULERS IN THE ANCIENT EMPIRE OF ROME. LET ONE EARTH YEAR BEFORE THE BEGINNING OF HIS DOMINION HELP YOU DECODE THAT WHICH IS SHROUDED BY HIS NAMESAKE: &|sr%uLdb4Cbfd09`55b?0`?0f9b0dA`4b0CbGbc=0A_HbC0_GbC0c==N

Don't waste your time on riddles, use dcode.fr! Flag was encoded with ROT-47.

Flag: UMDCTF{53cr375_h1dd3n_1n_7h3_5p1c3_r3v34l_p0w3r_0v3r_4ll}