We were given a GIF of a person waving a flag. The objective was to extract the hidden flag from the GIF.

Extracted each frame from the GIF

Observing the frames, the person was waving the flag in a pattern resembling semaphore signaling

Using a military semaphore flag reference, we translated the positions of the flags in each frame into letters.

The decoded sequence gave the following string:
QBAAAEFAAAAGOADBEEAAAEAAGDENPAKADABAEAKAAAAABOBIOHKLHGPOAHPKGAPKNNBMEIABIAAPLJDIOAAAAABABAIAKLPENIEAIONHODKKAEHEFFECACPGGGMGBGHCOHEHIHECAEIFEFEFACPDBCODAANAKEMGJGOGLCNEMGBHJGFHCDKCAFCEGEDCNDEDIDCDECNHDGFGNGBHAGIGPHCGFANAKANAKAAAAR

The decoded text seemed like an encoded format
identified it as a substitution cipher

It gave a hex value

After converting the hex values into text, we found a file name flag.txt

The content of flag.txt contained the final flag for the challenge