The "flag" is usually the final prize, often formatted as FLAG{...} or CTF{...} . In some forensics challenges, the flag may be hidden in the ZIP's or within alternative data streams (ADS) if the file was handled on a Windows system.
: Run unzip -l Space.Invaders.Extreme.zip . Common contents might include: An executable ( .exe or ELF) related to the game. File: Space.Invaders.Extreme.zip ...
Depending on what was found in the archive, use these specialized techniques: The "flag" is usually the final prize, often
: Use these tools to see if other files are embedded inside the extracted files. For example, a PNG file might actually have a ZIP appended to the end of it. File: Space.Invaders.Extreme.zip ...