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How to block VPN apps?

Hi all,

I have a XG 550. I would like to block VPN apps like X-VPN, UltraVPN or something like that.
I created an application filter policy following this guide https://community.sophos.com/kb/en-us/123108

I also block all proxy and VPN app listed in Application Filter Criteria.

But user still can use X-VPN to bypass the XG.
My XG running 16.05.8.

Please give me some advice.
Thank you.



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  • Create an Application Filter policy with below details :

     

    1. Block 'Proxy and Tunnel' category.

    2. Block Category - Category = ALL except Proxy and Tunnel, Characteristics = Can bypass firewall policy.

    3. Block 'DNS Multiple QNAME'.

     

    Web Filter - Block Anonymizers, Peere-to-Peer on HTTP, HTTPS.

     

    Create a Test rule on top for one machine and apply this. Keep on top of even DNS rule. 

     

    If it doesn't work, go to console and increase max packets to 100.

    set ips maxpkts 100

     

    Let us know if it works.

     

  • Thanks for your advice.
    I did it but it won't help. It can block other VPN apps like FastVPN, UltraVPN but can't block X-VPN.
    I see that X-VPN use 7 protocols. After adjusting the policy following your instruction, XG just block 2 of those 7. And then X-VPN connected with the 3rd protocol. 

  • Hey, our school has employed a number of security and IT specialists. They work with a company called Linewise which claims to filter SSL and HTTPS. They are unable to block X-VPN. Also let me know if SkyVPN and Psiphon VPN work on your network.

    School needs to allow google apps because most of our learning is based around school. X-VPN uses api URLs such as 8v9m.com and tubnet.com I can provide a list if needed as giving this to my IT hasn’t really resulted in any success. Safe search is enabled.

    Even deompliling their iOS app, android app and their Mac and chrome extension, I was able to find a premium server list. Blocking IPs don’t even work and since using their method called pretendauthtls they work similar to openvpn ssl meaning it is difficult to detect.

  • Hi,

    I have been experimenting with my firewall rules.

    You  need a two pronged approach:-

    1/. web filter rule - xvpn.io and x-vpn.io deny

    2/. you need an application rule blocking proxy and tunnel as well as p2p sites.

     

    If you need specifics I will copy my rules for you. Mind you I think I have broken neighbours work tunnel. I will build a new set application rues for my specific access.

    Ian

    XG115W - v20 GA - Home

    XG on VM 8 - v20 GA

    If a post solves your question please use the 'Verify Answer' button.

  • Hi guys, thank you for your all comments. Actually I opened a ticket support. There were at least 3 technical joined that ticket. Finally I received the best answer from the senior technical:

    - We expect user machine having Sophos Secure certificate available and installed on user machine as this is require HTTPS scanning needs to be enable in firewall rule which is there and without this setting XG will not take action on application traffic.

    For reference, please follow below KB article for adding certificate on user machine.

    https://community.sophos.com/kb/en-us/123048

    - Goto Protect > Web > Protection > Click on Advance and Enable below settings.

    > Enable Pharming Protection.
    > Block unrecognized SSL protocols.

    It could help. But we must installed the certificate on all devices joining the network. Is it possible? And somehow that settings also made some troubles with other apps like Facebook or Whatsapp.

    In general, it is impossible to block X-VPN in the simplest way by Blocking X-VPN category. And if you block X-VPN in any cost, some other apps will get issue.

  • Hey, so this method will basically look for anything sent in the headers. If there is anything in the headers to suggest it is a vpn it will be blocked. This method is essentially a man in the middle attack and will break most https sites if they have certificate pinning.

    If it helps, x-Vpn is partly written in go and some of the files it “steals” it’s code from are from GitHub.

  • This is a client and they are using they are using x-vpn to get past all of the other rules. What they don't know is that we are aware of what they are doing... :D

  • Are you aware of what other apps will have issues?  As this is a corporate client I have to be careful what I am blocking!

    They have VPN connections set up to access the server from 4 different locations and run a couple of different programs on it.

    Thanks kindly!

  • In my case, facebook can't load the image, whatsapp on mobile can't connect.

  • Sophos XG (SFOS 17.1.3 MR-3) is NOT blocking a number of VPN apps including X-VPN and Psiphon so our students are able to bypass all firewall rules and web filters. Enabling "Decrypt & Scan HTTPS" does not make any difference either. 

    I came across this post recently and unpleasantly surprised that 5 months later Sophos has not developed updated application filters rendering the Sophos XG firewall useless in a school environment. I have raised a support ticket with Sophos and will post feedback once I hear back from them. I manage a number of Sophos firewalls for schools and think it's time to consider other options. Fortigate is looking increasingly good!!!

  • Thank you envercpt for your information. School environment is also exactly what i'm experiencing. Students always try to bypass the firewall. 

    I was creating a ticket support. The Sophos guy instructed me to do many many things and it looked block the X-VPN. But it also made difficult using other apps like whatsapp, facebook. 
    Anw, i'm looking forward from hearing the result from you. 

  • In a corporate environment errant employees can be fired. Difficult to fire students ;-)

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