VPN Monitoring Bundle

Shout out to Paco for laying the groundwork for the VPN initiative and Pete/Kanen for the original trigger work. Really just posting on their behalf.

The crux of this VPN monitoring approach is the creation of a VPN Custom Device on which we can aggregate metrics and filter trigger executes only to the VPN traffic. There is a discussion for other deployment models (device group, L3 device discovery, etc) that might be more appropriate for other customers. The current trigger is designed to be very minimal in processing and should be able to be deployed to most environments without any concerns.

What do I get?

A network-focused view of VPN usage and performance.

Current Bundle:

VPN Network Monitoring (v1.7.0).json (153.5 KB)
Change log:
Modified charts to take advantage of more built-in metrics
Modified layout and style of several charts

Previous Versions:

VPN Network Monitoring (v1.6.2).json (158.9 KB)
VPN Network Monitoring (v1.6.1).json (157.9 KB)

1x Trigger – VPN Network Monitoring
1x Dashboard – VPN Monitoring

(Dependency on the Active Directory Rx trigger)

Internal and Internet-bound traffic breakdowns

Protocol Breakdown

Includes classification for VoIP traffic streams for several teleconferencing solutions. The trigger can be modified with additional port ranges for other solutions as required by the customer.

User-IP mappings and teleconference-specific network utlization tracking

Discussion

  • Where possible, enterprises should split tunneling to avoid excess VPN load. I like to use Proof-Negative charting (Evidence of Absence), dashboards which we want to see blank. Teleconference traffic is a good example of traffic which should be sent directly to the internet.
  • When accessing and manipulating large resources like DB and large files, consider whether a VDI solution could be used to reduce VPN load and improve performance for the end user
  • The attack surface has increased exponentially, with the need for rapid expansion of remote workers, understanding which users are currently tied to VPN IP’s will enable faster threat isolation

Questions the dashboards answer:

  • How much traffic is going over my VPN? How much of that is internet traffic vs. internal traffic?
  • How much bandwidth are the users consuming? Are they having congestion related issues?
  • How much traffic is Webex, Zoom, GoToMeeting, etc?
  • Who are the users consuming the most bandwidth and what type of traffic is that?
  • What files are users pulling down to home computers? Is that normal behavior for that user?
  • Who is the user that had malware or something malicious on their home computer?

Deployment

  1. Make sure Network Localities are properly configured as they are used for Internal vs Internet traffic.
  2. Create a custom device for all of the VPN subnets
  3. Assign the Trigger VPN Network Monitoring to the custom device. The trigger has three modifiable flags
    a. ad_bundle_active – Leave set if the AD bundle is active and you are going to use the IP-User mapping in that bundle. If set to false, the bundle will currently not perform any user mapping, though the code is in place to expand how users are determined.
    b. check_teleconference_ports – Set to false if the customer does not care about teleconference protocols or split tunneling has been validated. This will reduce some cycle load for the trigger
    c. commit_records – There is no Record Format in the bundle currently, so this is defaulted to false. As we extend the bundle functionality, we will include the appropriate Record Format and set the default value to true
  4. Modify the Active Directory trigger and set the flag const storeUserInSessionTable = true; (Line 50 in Rx v1.2)
  5. For the VPN Monitoring Dashboard, Modify Source to the custom device.
    image

Extending Functionality

Modifying Teleconferencing Port Ranges

The port ranges and platform port mappings are stored in the mapTeleconfPort function. To add additional ports, select the correct IPProto (tcp/udp) and add the port range to the list. For single value ports, use the port for both upper and lower bounds.

const vpn_teleconf_mapping = cache('vpn_teleconf_mapping', () => ({
        'tcp': [
            [5004, 5004, 'Webex'],
            [5090, 5091, 'Zoom'], 
            [8801, 8802, 'Zoom'],
        ],
        'udp': [
            [1853, 1853, 'GoToMeeting'],
            [3478, 3481, 'Zoom/Teams/Skype'],
            [5090, 5091, 'Zoom'],
            [7500, 7501, 'Webex'],
            [8200, 8200, 'GoToMeeting'],
            [8801, 8810, 'Zoom'],
            [9000, 9000, 'Webex'],
            [19302, 19309, 'Hangouts Meet'],
            // [20000, 64000],
            // [50000, 60000],
        ]
    }));

Add additional User-IP mappings

The getUser function maps an IP address to a username. Today the only mapping used is the AD Bundles Kerberos parsing, which is then stored on the Session Table. This can be expanded to use other auth methods, including replicating the AD bundle and assigning just to the VPN custom device.

function getUser(ipaddr) {
    let username;

    if (ad_bundle_active) {
        username = Session.lookup("AD_User_" + ipaddr);
        debug(`User from session table: ${username}`);
    }

    // TODO: Replicate AD Kerberos parsing 

    // TODO: Build other auth methods based on customer requirements

    return (username ? username : ipaddr);

}

I added the client VPN address pool from each on my GlobalProtect PANs as a Custom device but it still won’t show any metrics for internet traffic. Should that CIDR be added as external traffic?

@mariode You want to have the internal VPN concentrator CIDRs . When you navigate to the custom device directly, do you see metrics? You can type the name you gave the custom device into the global search in the upper right to navigate to the Custom Device.

image

A few issues I have seen, check and make sure the device is in advanced analysis

image

If you click “Edit Assignments” and click the Triggers Tab, make sure the VPN Network Monitoring trigger is assigned. If it’s not, you can assign it here.

image

Finally, check that the VPN Monitoring Dashboard has your custom device as a source

image

Hopefully that helps.