Level goal

To gain access to the next level, you should use the setuid binary in the homedirectory. Execute it without arguments to find out how to use it. The password for this level can be found in the usual place (/etc/bandit_pass), after you have used the setuid binary.

Login

ssh bandit19@bandit.labs.overthewire.org -p 2220
cGWpMaKXVwDUNgPAVJbWYuGHVn9zl3j8

Solution

When using ls in homedir, you can see the presence of bandit20-do. Running it with the prefix ./ gives you the ability to execute commands with the permissions of the user bandit20. Therefore, you could just cat the contents of /etc/bandit_pass/bandit20 to get the password needed for the next level.

bandit19@bandit:~$ ls
bandit20-do
bandit19@bandit:~$ ./bandit20-do cat /etc/bandit_pass/bandit20
0qXahG8ZjOVMN9Ghs7iOWsCfZyXOUbYO