So I wasn’t too happy with the kludginess of the network monitoring tool that I posted about earlier this week. It lagged and really wasn’t an ideal tool. I decided to redesign the entire model.
The new tool still utilizes Python 2.7 and consists of three parts:
Ping/Enumeration Script
RESTful Django Script
Tkinter Reporting GUI Script
Here is how they connect. The Ping/Enumeration Script, pings all devices given within a network range. Whenever it finds a new device, it runs a NMAP scan on the device then formulates a request to the server to notify it of the device scan results. The script will also notify the server when a device disconnects from the network (this was an issue with the old version).
The Django server manages a sqlite database containing scan results on all devices currently connected to the network. It will remove or add a device record based on the ping script’s RESTful HTTP request. The server can also return a list of all devices detected. This list is used by the GUI script.
The GUI script maintains a Tkinter dialog window that will circulate through all network connected device scan results. It first sends a GET request to the Django server asking for a JSON list of all connected devices. The script will then display each record found in the JSON. Each device record will appear in the GUI window for 20 seconds. After it has made the rounds through each item, it will make another call to the server for a fresh JSON to iterate through.
The Ping/Enumeration Script is basically the same as what I discussed earlier. The difference is, after data is collected, it is sent to the Django server in a POST request.
import commands, re, json, urllib2, binascii
PREFIX = "192.168.1" #Network prefix
MIN = "0" #Starting network address, eg 192.168.1.0
MAX = "12" #Closing network address, e.g. 192.168.1.55
results = []
def escapeMe(message): #Escape characters (using ASCII value) not allowed in JSON
new = ""
for num in range(len(message)):
char_code = ord(message[num])
if char_code < 32 or char_code == 39 or char_code == 34 or char_code == 92:
new = new + "%" + binascii.hexlify(message[num])
else:
new = new + message[num]
return new
def sendDevice(gotcha): #Send the device report to the server as a POST
try:
url = "http://127.0.0.1:3707/new/" #Server address
gotcha = escapeMe(gotcha)
values = json.dumps({'device' : str(gotcha)})
req = urllib2.Request(url)
req.add_header('Content-Type', 'application/json')
rsp = urllib2.urlopen(req, values)
code = rsp.getcode()
except Exception, e:
print e
def removeDevice(ip): #Send request to remove device
try:
ip = ip.replace('.','-')
url = "http://127.0.0.1:3707/remove/"+ip+"/"
rsp = urllib2.urlopen(url)
code = rsp.getcode()
except Exception, e:
print e
def main():
global results
while 1:
new = commands.getoutput('for i in {'+MIN+'..'+MAX+'}; do ping -c 1 -t 1 '+PREFIX+'.$i | grep "from"; done') #Ping sweep the network to find connected devices
tmp = re.findall(PREFIX+"\.(\d+)", str(new)) #Pull out IP addresses from the ping results
if tmp != results:
for ip in tmp:
if ip not in results:
gotcha = commands.getoutput('nmap -v -A -Pn '+PREFIX+'.'+ip) #nmap new devices found on the network
sendDevice(gotcha) #send device record to server
for r in results:
if r not in tmp:
removeDevice(PREFIX+'.'+r) #remove device if it wasn't found in the latest ping
results = tmp
if __name__ == "__main__":
main()
Django is an awesome Python Web Application Framework that I absolutely adore (not the movie 🙂 ). It is known as the web framework for perfectionists with deadlines. Most of my web projects utilize Django.
It comes with its own lightweight server to host its applications, so its perfect for any development environment. For the sake of this project, I’m using its server, all script/server functionality is limited to the host machine running the tool. Everything is internal. Django also handles the RESTful routing and database modeling. It uses the model view controller (MVC) structure. Here is a great tutorial on how to create your own Django app, definitely worth looking into!
The following is the break down of code I wrote for the Django server (running version 1.3).
####################models.py####################
from django.db import models
class Devices(models.Model):
device = models.TextField()
####################ADD to urls.py####################
url(r'^new/$', 'lilDevil.views.new', name='new'),
url(r'^listDevices/$', 'lilDevil.views.listDevices', name='listDevices'),
url(r'^remove/(?P*ip*.+)/$', 'lilDevil.views.remove', name='remove'), #REPLACE * with greater/less sign containing brackets
####################views.py####################
from django.http import HttpResponse
from lilDevil.models import Devices
import json
def remove(request, ip):
try:
ip = ip.replace('-','.')
devicelist = Devices.objects.all()
for d in devicelist:
if ip in d.device:
d.delete()
return HttpResponse(status = 200)
except Exception, e:
return HttpResponse(e)
Finally, the GUI script. Very similar to the one in the old post. Again, I just added the ability to request device data from the server.
from Tkinter import *
import time, urllib2, urllib, json
class flipGUI(Tk):
def __init__(self,*args, **kwargs): #Setup the GUI and make it pretty
Tk.__init__(self, *args, **kwargs)
self.label1 = Label(self, width= 65, justify=CENTER, padx=5, pady=5, text="Guests") #Text label
self.label2 = Label(self, text="") #Photo label
self.label2.grid(row=0, column=1, sticky=W+E+N+S, padx=5, pady=5)
self.label1.grid(row=0, column=0)
self.flipping()
def flipping(self): #Flip through NMAP scans of detected devices
t = self.label1.cget("text")
t = self.label2.cget("image")
data = getData()
found = json.loads(data)
photo = PhotoImage(file="picture.gif")
if found['devices']:
for f in found['devices']: #Loop through all but the last item
fixed = f['device'].replace('%0a', '\n') #return to ASCII value from earlier escaped hex
self.label1.config(text=fixed)
self.label1.update()
self.label2.config(image=photo)
self.label2.update()
time.sleep(20)
else:
self.label1.config(text="No connected devices")
self.label1.update()
time.sleep(20)
self.after(1, self.flipping())
def getData(): #Get a list of devices from server
url = "http://127.0.0.1:3707/listDevices/" #server address
response = urllib2.urlopen(url)
code = response.getcode()
if int(code) == 200:
return response.read()
else:
return
if __name__ == "__main__":
try:
while 1:
app = flipGUI()
app.mainloop()
except Exception, e:
print e
Final Note: Make sure to delete/clear out database or old results will carry over! I did this in an init.d script that calls the service.
Put it all together and you have a much more stable tool. I renamed it from the Hindenburg to the Lil Devil.
UPDATE: I made a better version of this tool with server implementation here.
Today I felt like building a python 2.7 script that would enumerate a network along with alert me to the presence of a new device.
I limited my project to functions in the standard library.
So something lightweight and okay fast is a ping sweep. From an early post I included the Linux command for a sweep. I used this command along with the python commands to execute the ping sweep along with storing the results in a variable.
new = commands.getoutput('for i in {'+MIN+'..'+MAX+'}; do ping -c 1 -t 1 '+PREFIX+'.$i | grep "from"; done')
Following, I used some regular expressions to pull out the IP addresses detected in a given prefix range.
tmp = re.findall(PREFIX+"\.(\d+)", str(new)) #Pull out IP addresses from the ping results
Put that in a loop with some comparison data and you have a script that prints an alert whenever a new device is detected.
import commands, re
PREFIX = "192.168.1" #Network prefix
MIN = "0" #Starting network address, eg 192.168.1.0
MAX = "12" #Closing network address, e.g. 192.168.1.55
results = []
while 1:
new = commands.getoutput('for i in {'+MIN+'..'+MAX+'}; do ping -c 1 -t 1 '+PREFIX+'.$i | grep "from"; done') #Ping sweep the network to find connected devices
tmp = re.findall(PREFIX+"\.(\d+)", str(new)) #Pull out IP addresses from the ping results
if tmp != results:
for t in tmp:
if t not in results:
print "New device at" + PREFIX + "." + str(t)
results = tmp
There are a few short comings in the code but that’s the basic idea.
Now take this further, I hooked it up to a GUI with enumeration information! The new beastly application constantly flips through NMAP scan results of devices found connected to the network and displays the results in a GUI. I even placed a picture in the GUI. I call this app, the Hindenburg, its kind of hacked together.
from Tkinter import *
import time, commands, re
PREFIX = "192.168.1" #Network prefix
MIN = "0" #Starting network address, eg 192.168.1.0
MAX = "12" #Closing network address, eg 192.168.1.12
class flipGUI(Tk):
def __init__(self,*args, **kwargs): #Setup the GUI and make it pretty
Tk.__init__(self, *args, **kwargs)
self.label1 = Label(self, width= 65, justify=CENTER, padx=5, pady=5, text="Guests") #Text label
self.label2 = Label(self, text="Guests") #Photo label
self.label2.grid(row=0, column=1, sticky=W+E+N+S, padx=5, pady=5)
self.label1.grid(row=0, column=0)
self.flipping()Â Â Â Â def flipping(self): #Flip through NMAP scans of detected devices
t = self.label1.cget(“text”)
t = self.label2.cget(“image”)
found = scanNetwork()
photo = PhotoImage(file=”picture.gif”)
for f in found[:-1]: #Loop through all but the last item
self.label1.config(text=f)
self.label1.update()
self.label2.config(image=photo)
self.label2.update()
time.sleep(15)
self.label1.config(text=found[-1]) #the last item doesn’t require the sleep, it takes enough time to run the scans
self.label1.update()
self.label2.config(image=photo)
self.label2.update()
self.after(1, flipping())
def scanNetwork():
found = []
new = commands.getoutput(‘for i in {‘+MIN+’..’+MAX+’}; do ping -c 1 -t 1 ‘+PREFIX+’.$i | grep “from”; done’) #Ping sweep the network to find connected devices
tmp = re.findall(PREFIX+”\.(\d+)”, str(new)) #Pull out IP addresses from the ping results
for ip in tmp: #Loop through each found IP
found.append(commands.getoutput(‘nmap -v -A -Pn ‘+PREFIX+’.’+ip))
return found
app = flipGUI()
app.mainloop()
It’s ideal for an environment where it can just sit on the screen without much of any type of activity going on. If you are enumerating the entire network, there will be a lag… it happens.