Clear it in 3 steps
Start the environment
Investigate the target
Submit the flag

Recover deleted text files from the disk image and find the flag. Learn how to use file carving tools to recover deleted files. Provided file: disk_image.dd
Try using tools called foremost or scalpel
You can recover files with: foremost -i disk_image.dd -o output/
The flag is in one of the recovered text files