Overview
We’re tasked with tracking down someone’s social media post and extracting the flag from it. Let’s get started.
Solution
The challenge description states that our target registered on a social media site recently. Looking at the name of the challenge, we can make a guess as to which social media platform our target is on: BlueSky.
Searching for the post
Most social media sites support “advanced” search via search filters, and BlueSky is no exception. Using a filter (referenced here) let’s search for posts that match certain attributes. In this case, we’re interested in seeing all posts from our target, allnaturalhacking, so we’ll use the from: filter:
from:allnautralhacking.bsky.social
This gives us one result: A post containing a weird-looking string:
JVSXIYKDKRDHWNDJNY3V6QC7MMYTA5LEL4YW4XZVGFTWQN35
The challenge description mentioned the target using Base32, so we can pop the string into CyberChef and select the Base32 recipe or run a command like the one below, both of which give us the flag:
┌──(kali㉿kali)-[~]
└─$ echo "JVSXIYKDKRDHWNDJNY3V6QC7MMYTA5LEL4YW4XZVGFTWQN35" | base32 -d
MetaCTF{4in7_@_c10ud_1n_51gh7}