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Any experience with an excessive number of ThunderVPN hits?

I recently set up a new XG firewall at our main branch location in order to assist with IPS and application control service.   I am currently using the "Block high risk (Risk Level 4 and 5) apps" setting for app control.

What I am noticing is a large amount of ThunderVPN hits on our network, and I'm at a bit of a loss on what could be causing this traffic.  I'm glad they are being blocked, but I wanted to see if anyone had any experience with this and what might be utilizing this service.

Our entire network consists of Dell workstations and the traffic is coming from various IP addresses, not just one machine.

Thanks in advance for any information!



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  • I forwarded this pcap to Labs. But they have to analyze the traffic and find the root cause. More pcaps submitted by the process above would be helpful to find the pattern. 

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Children
  • I see, ok.  I submitted last night the same pcap and conntrak files at the file submission link you shared above.  It created a case (04501211).  Over night it was looked at and closed.  The comments for each file were "not detect-worthy" ... and the overall comment was "This means that after investigation and analysis of the file SophosLabs has come up to a result that the sample submitted is not malicious, not showing any malicious behaviour and properties."

    I don't know what else to do here.  I opened a support case on this issue earlier in October.  After about 4 days I finally talked to a tech and he went down the workaround route for the issue for the time being, which I have done.  That case (04447658) was then closed.

    It seems pretty straightforward here to me.  Someone at Sophos Labs needs to go back and see what changes were made in the 18.18.56 IPS/App signatures on 9/23 and roll them back with respect to NTP traffic on UDP/123 and Thunder VPN.  Why someone would blanket presume that well known UDP port 123 NTP traffic was Thunder VPN is beyond me.  I have multiple client devices on my network unable to get NTP updates with this issue present.  I have Apple products, I have Microsoft products, I have other IoT devices, I have Hikvision security cameras.  Heck, I can reproduce this AT WILL with my Apple MacBook Pro laptop.  There is no Thunder VPN in my network.  My Hikvision cameras do not have Thunder VPN on them.  But yet all ~35 endpoints on my network can't get NTP updates with this IPS/App filter post 18.18.56.

    Feel free to take these two case numbers back internally and see what else you can do.  I appreciate the help as I don't know what else I can as a support paying Sophos XG customer.  But I'll tell you, this support experience (frankly it's my first real one) isn't leaving me with a positive impression.

  • Did you create a Submission or a Application Control Submission?
    BTW: ThunderVPN uses Port 123 to connect. It is a cheap way to hide behind port based app controls. 

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  • I submitted it as "Application Control" ... was that incorrect?  Should I choose "Sample File" instead?  Thanks for the added info on how Thunder VPN uses ports.