The flag06 account credentials came from a legacy unix system. To do this level, log in as the level06 account with the password level06. Files for this level can be found in /home/flag06.
There is no source code available for this level
sed -n '37 p' /etc/passwd > /tmp/crack_pwd
flag06:ueqwOCnSGdsuM:993:993::/home/flag06:/bin/sh
john crack_pwd ----> password: hello
john --show crack_pwd
su flag06 <---- hello
/bin/getflag