Challenges: (ranked roughly from easiest to hardest)
 -  put user in a python shell, have them try to read the flag from a file
 -  `2l.sh` - read flag from a file using only 2-letter shell commands
 -  `approved.pl` - read flag from file using only the commands `ls`, `pwd`, `whoami`
 -  `squeal.sh` - perform an SQL injection attack to read the secret flag from the `flags` table
 -  `patience.c` - find the code from a binary executable that will print the solution in 1 year's time

Make sure there is a different flag for each challenge.