Test Authentication from Linux Console using python3 pexpect

Working with the IT420 lab, you will discover that we need to discover a vulnerable user account.  The following python3 script uses the pexpect library to auth with a defined username and password.  This can be used to discover an account.

#!/usr/bin/python3

# Found the script at https://stackoverflow.com/questions/5286321/pam-authentication-in-python-without-root-privileges and then modified
import pexpect
def authPam(username, password):
        result = 0
        try:
                child = pexpect.spawn('/bin/su - %s'%(username))
                child.expect('Password:')
                child.sendline(password)
                result=child.expect(['su: Authentication failure',username])
                child.close()
        except Exception as err:
                child.close()
                print ("Error authenticating. Reason: "%(username))
                return True
        if result == 0:
                print ("Authentication failed for user %s."%(username))
                return True
        else:
                print ("Authentication succeeded for user %s."%(username))
                return True

if __name__ == '__main__':
        authPam(username='root',password='root')
        #authPam(username='kali',password='kali') - If the user does not exist the script implodes...