For loop in BASH to get username and password tuple

Question

I am writing a simple script with Bash 4.4.23, to perform a demonstrative dictionary attack towards various web servers which use default passwords.

The arrays containing usernames and passwords are declared above the "for" cycles, which are as follows:

for i in $usernames
do for j in $passwords
    do printf '%s ' "${usernames[*]}:${passwords[*]}"
done
done

The code should return something like:

root:root root:admin admin:admin admin:root

But instead it is returning

root admin:root admin

Which are the values declared within the arrays (usernames and passwords).

How can I achieve what I'm trying to do? The tuples will then have to be passed to curl in order to perform the dictionary attack.

Answer 1

You have the arrays and the elements you loop over mixed up. You loop over the array. You use the loop variable inside the loop.

for i in "${usernames[@]}"
  do for j in "${passwords[@]}"
    do printf '%s:%s ' "$i" "$j"
  done
done

The symptom you see is because $usernames alone refers to the first element of the array, and similarly for the other array variable.

Answer 2

wildcard wont work here. Try

for i in $usernames
do for j in $passwords
    do printf '%s:%s ' "$i:$j"
done
done