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I have been asked to do a paper on Whatsapp for Networks (college class). As far as I know, it is based on XMPP. But I can't find any of its packages on the WireShark process (using whatsapp web), only TCP protocols.

I have downloaded the Packet Tracer for Android and it has given me some TCP packages on hex.

How can I analyze it? Is it XMPP? Is it TCP? How can I have the ACK or the SYN ACK bits on the tracer? what about the RTT?

Is there any better program for this analysis?

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    Are you trying to analyze how TCP handshake works? How TCP works in general? How WhatsApp security works? How to see messages being sent? Some clarification needed, please. – sysfiend Feb 7 '17 at 16:55
  • Hi! Actually I have been asked to simuate a scenario with the Whatsapp Service. I was trying to use the Cisco Packet Tracer(which includes DHCP , DNS , SMTP etc) but it doesn't have the XMPP service. Therefore I cannot simulate it. So, after running Wireshark and acessing Whatsapp web i could only see the TCP communication but no XMPP , I guess because it is encrypted , right? So the only alternative that is left is for me to analyze the TCP packets between the whatsapp server and my computer right?Or is there any other way to analyze whatsapp packets or simulate it? – Luis Filipe Feb 7 '17 at 17:40
  • How to see messages being sent would be great too. It is hard to understand those hexdecimal on the wireshark. – Luis Filipe Feb 7 '17 at 17:58
  • Without continuous working and learning, you won't be ever a successful programmer. What you don't want to start now, this is what you will do in your whole life. – peterh says reinstate Monica Feb 9 '17 at 21:55
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You won't see anything relevant in Wireshark because the communications between WhatsApp users happen using private and public keys. Here's how it works in practice:

  • A wants to send a message to B.
  • A firstly asks B for his public key (every user generates around 100 public keys attached to one single private key).
  • A then encrypts the message using B's public key and sends it.
  • B recieves it and, using his private key, decrypts it.

So, without breaking this scheme, you won't be able to read those packet's data.

In case you are just analyzing TCP, you will be able to see the handshake as usual with it's ACKs, FINs, etc.

  • So what you are saying is that with Wireshark i can only reach and analyze the TCP right? Is there any other program that i can capture the whatsapp packets? – Luis Filipe Feb 7 '17 at 18:29
  • @LuisFilipe the problem here is not capturing them, but seeing it's data. In order to do so, you'd have to break the encryption system faking B's private key (pro tip: you will need some billion years to do so, don't try it at home :d) – sysfiend Feb 7 '17 at 18:32
  • Hahaha , well that is just not much encouraging! Hope the professor understand that. Thank you very much! Btw, about 5 years ago it was possible to break the encryption right? There was an extesion for the wireshark. – Luis Filipe Feb 7 '17 at 18:37
  • @LuisFilipe you can always break it if it's not strong enough, it's a matter of time and using vulnerabilities found on the algorithms used. – sysfiend Feb 7 '17 at 18:39
  • The image of my attempt to reach the whatsapp server i have few questions(scontent.fplu9-2.fna.fbcdn.net/v/t1.0-9/…) 1)What is the TCP SYN segment sequency number used to start the TCP connection? 2)What is the sequency number and the ACK number of the SYN ACK package? How do you identify a SYN ACK package? 3)What is the sequency number of the first TCP segment which contains the HTTP POST command? Is it possible to answer those question with the WireShark Whatsapp TCP analysis?? – Luis Filipe Feb 7 '17 at 18:48
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Whatsapp Web works in the browser, it requires only a browser, without any add-ons. Thus, it uses obviously https or at most some of its extensions (websockets, etc).

The application-level protocol is embedded into this. It is possible, but not probable, that it uses also an intermediate XMPP layer.

To analyze them, first you have to break the https (or any other browser-supported) encryption layer.

  • Hi, what do you mean by break the https encryption layer?(I'm really new at this). Thanks! – Luis Filipe Feb 7 '17 at 18:18
  • @LuisFilipe It is https. Https is the encrypted protocol on which the browsers mostly communicate. It doesn't use XMPP (although it is possible that it uses XMPP communication embedded into the https traffic). To do this, first you have to crack the https and see, what is in it. – peterh says reinstate Monica Feb 7 '17 at 18:43
  • Well , after reviewing my attempt of connection on whatsapp web the only services i can relate to are: Ethernet TCP IPv4 SSL I don't see any http services on the list – Luis Filipe Feb 7 '17 at 19:09
  • @LuisFilipe On which tcp ports is it working? 443? – peterh says reinstate Monica Feb 7 '17 at 19:51
  • Yes , it is working on 443. As you can see on this image: scontent.fplu9-2.fna.fbcdn.net/v/t1.0-9/… This was my attempt to reach the Whatsapp server on whatsapp Web – Luis Filipe Feb 7 '17 at 20:13

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