Script to periodically change the MAC address of an interface an reconnect to WiFi in Ubuntu. Can be used for circumventing public WiFi limits. Has been tested with "WIFIonICE" WiFi from Deutsche Bahn.

wifileech.sh

#!/bin/bash
set -euo pipefail
#set -x

change_mac(){
  OLDMAC=$(ip link show wlan0 |grep -oP '([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})'|head -1)
  ifconfig ${1} down
  set +e
  while true
  do
    sudo macchanger -ea ${1} 2>/dev/null
    if [ $? -eq 0 ]
    then
      break
    else
      printf "."
      sleep 1
    fi
  done
  set -e
  ifconfig ${1} up
}

reconnect(){
  set +e
  while true
  do
    iwlist wlan0 scan > /dev/null 2>&1
    if [ $? -eq 0 ]
    then
      break
    else
      printf ":"
      sleep 1
    fi
  done
  set -e
  systemctl restart NetworkManager
  set +e
  while true
  do
     curl -s --connect-timeout 10 "http://www.wifionice.de/de/" \
          -H "Host: www.wifionice.de" -H "User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:58.0) Gecko/20100101 Firefox/58.0" \
          -H "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8" -H "Accept-Language: en-US,en;q=0.5" \
          --compressed -H "Referer: http://www.wifionice.de/" -H "Content-Type: application/x-www-form-urlencoded" \
          -H "Cookie: csrf=42" -H "Connection: keep-alive" -H "Upgrade-Insecure-Requests: 1" \
          --data "login=true&CSRFToken=42&connect="
    if [ $? -eq 0 ]
    then
      break
    else
      printf "-"
      sleep 1
    fi
 done
 set -e
}

validate(){
  if [ -z "${1}" ]
  then
    echo "Please add an interface with '-i'."
    exit 1
  fi

  if ! [[ $2 =~ ^[0-9]+$ ]]
  then
    echo "Rerun interval not numeric."
    exit 1
  fi

  if [ "$EUID" -ne 0 ]
  then
    echo "Please run as root."
    exit 1
  fi
}

while getopts ":i:r:" opt; do
  case $opt in
    i)
			MYIF=${OPTARG}
      ;;
		r)
			SLEEPTIME=${OPTARG}
			;;
    \?)
      echo "Invalid option: -$OPTARG" >&2
      exit 1
      ;;
    :)
      echo "Option -$OPTARG requires an argument." >&2
      exit 1
      ;;
  esac
done

SLEEPTIME=${SLEEPTIME:-0}

# Not always valid, works for my notebook
MYIF=${MYIF:-wlan0}

while true
do
  validate "${MYIF}" "${SLEEPTIME}"
  change_mac "${MYIF}"
  reconnect

  echo -e "\nMAC change successful."
  if [ "${SLEEPTIME}" -gt "0" ]
  then
    echo "Now sleeping ${SLEEPTIME}s."
    sleep ${SLEEPTIME}
  else
    break
  fi
done

Rev. 2:

• Now using GNU macchanger to get valid MACs
• New curl URL and command, taken from https://gist.github.com/dicer/b21300fbbfdd8cf011756a8673b6f69c