Challenge
All that was given was the text and that skull emoji. There were no files, no network services, just that. The idea was that the whole hidden message and flag were stored inside the emoji itself, since I heard about smuggling text inside emojis as a prompt injection techniuque.
Step 1 --- Initial Analysis
So i copied the entire description just to be sure and pasted it inside the OpenAI tokenizer revealing following weirdness:
Step 2 --- Solving
It was clear that there was a hidden unicode message inside the skull emoji, so I went input the emoji into the following site: emoji.paulbutler.org, a tool that can hide or reveal messages inside emojis and letters.
All I did was copy the emoji string into that website, switched the mode to Decode, and it immediately revealed the hidden message, which also included the flag. Nothing else was needed. The whole thing was already inside that single emoji string.
Step 3 --- Result
After decoding on the site, the hidden text showed the flag clearly:
Notes
It was probably intended to be used with an AI prompt, since when you feed the emoji string into one it likely replies with "I have no idea what is this quack" instead of decoding it. Thatβs probably a small rabbit hole meant to mislead solvers. The real solution was simply to decode it directly since the whole flag was already inside the emoji string.