This is a post in a series where I complete every Flare-on challenge. The landing page for all of these posts can be found here
Starting off the 5 series of challenges we have a very simple password challenge, when extracting the archive you have one file extracted.
MinesweeperChampionshipRegistration.jar: Java archive data (JAR)
When running the file, you are prompted for an invitation code. I unzipped the jar file finding the metadata and a class file. I ran strings on the class file and was able to see the flag in plain text in the file.
After entering the flag shown in strings into the prompt it is validated!