Description
How about some hide and seek?
Setup
Download the file and unzip it to expose ukn_reality.jpg.
All work happens locally with command-line tools.
wget https://artifacts.picoctf.net/c_titan/6/unknown.zip && \
unzip unknown.zip
Solution
- Step 1Inspect EXIF metadataUse exiftool to dump every field. The Attribution URL entry stands out because it holds a Base64-looking string rather than a normal link.exiftool ukn_reality.jpg
- Step 2Extract just the encoded valueA quick pipeline can isolate the Attribution URL value, strip whitespace, and hand the text to base64 -d. The decoded output is the entire flag.exiftool ukn_reality.jpg | grep "Attribution URL" | cut -d":" -f2 | tr -d " " | base64 -d
Flag
picoCTF{ME74D47A_HIDD3N_a6d...}
Decoding the Attribution URL entry reveals the complete flag shown above.