After extracting the file from zip, we got a Andriod Backup

Upon google, we found a way to extract the file

( printf "\x1f\x8b\x08\x00\x00\x00\x00\x00" ; tail -c +25 backup.ab ) | tar xfvz -

and we got 2 folders apps and shared

and we found this picture, the flag is at the bottom of the paper

HTB{ThisBackupIsUnprotected}