Problem: Matryoshka dolls are a set of wooden dolls of decreasing size placed one inside another. What’s the final one? Image: this
File: THE_FILE
Solution:
binwalk dolls.jpg -Me
Like the name implies, the image has zip files within it eventually after unzipping it all you get a file marked: flag.txt
cat flag.txt
picoCTF{4cf7ac000c3fb0fa96fb92722ffb2a32}
Flag: picoCTF{4cf7ac000c3fb0fa96fb92722ffb2a32}