Advanced Privacy and Anonymity Using VMs, VPN’s, Tor – Part 6

Advancedby mirimir (gpg key 0x17C2E43E)

Creating pfSense® 2.2.6 VMs as VPN Clients

Introduction

At this point, if you’ve followed Setting Up Secure Host Machines, your new VM host machine can only access the Internet through your chosen direct-connect VPN service. If you’ve followed Installing VirtualBox and Creating Linux VMs, you’ve created Linux workspace and LiveCD VMs. By default, their network adapters are NATed to the host machine, and they reach the Internet through your chosen direct-connect VPN service.

This tutorial covers creating pfSense® 2.2.6 (hereinafter “pfSense”) router/firewall VMs, configuring them as VPN clients, and testing for leaks using Wireshark. Your Linux workspace and LiveCD VMs will access the Internet through nested chains of these VPN gateway VMs and Tor gateway VMs, as discussed in Planning Advanced VM and VPN Setup. Using Tor gateway VMs is covered in Paying Anonymously with Cash and Bitcoins and Creating Nested Chains of VPNs and Tor.

If you want the host machine to routinely access the Internet directly, you can create a pfSense VM client for your chosen direct-connect VPN service. You can use that in your nested VPN chains, instead of the VPN client on the host machine, and connect via the VPN client on the host machine only when you want to hide software downloads or whatever. However, if you’ve chosen the high-privacy option, it’s crucial to continue using the host machine client for your direct-connect VPN.

Create New VPN Account

Your VM host machine is still using your direct-connect VPN service. The first pfSense VPN-client VM that you create can use either that VPN service, or another that will connect through it. It’s best to use a second VPN service for your first pfSense VM, in order to avoid leaks during the host-client to VM-client transition.

You’ll need an account with another VPN provider. It’s best to start with a free VPN service, because there’s no money trail. There are bandwidth and usage limits, however. Paying Anonymously with Cash and Bitcoins covers methods for anonymously buying VPN services.

Although SecurityKISS has a good free option, it does require an email address. But you can use free webmail accounts. The fastest (and perhaps most anonymous) option is AnonBox from the Chaos Computer Club. But accounts last at most one day, and are deleted after messages have been read. For persistent accounts, VFEmail is a good choice, because it only asks for a name.

It’s OK to use the host machine (running the direct-connect VPN) for this. For better isolation, you could dedicate a Linux VM (possibly full-disk encrypted) for this and other sensitive work on the host machine. Once you have a client ID and password from SecurityKISS, download the OpenVPN configuration files for Linux.

Creating & Configuring pfSense VM

Download “pfSense-LiveCD-2.1.5-RELEASE-amd64.iso.gz” from pfSense’s Coltex (Amsterdam, NL) mirror to the host machine (using the direct-connect VPN) and extract the installer image.

Create a pfSense VM, basically as described for Linux VMs in Installing VirtualBox and Creating Linux VMs.

  1. Select BSD as the OS, and FreeBSD (64 bit) as the version.
  2. Specify 512MB memory.
  3. Create a new hard disk using the defaults (VDI, dynamically allocated, 2GB) and finish.
  4. Then tweak the settings. Change the boot order to Hard Disk, CD/DVD and enable PAE/NX.
  5. Add the installer image to the virtual CD/DVD drive.
  6. Disable audio and USB support.
  7. Leave the default network adapter «Adapter 1» attached to NAT (host) and don’t change advanced settings. If this VM will connect through another pfSense VPN-gateway VM, however, attach this adapter to its internal network.
  8. Add a second network adapter «Adapter 2» and attach it to an internal network named, for example, pfS-SK (but don’t change advanced settings).
  9. Start the pfSense VM. In the console window, hit 1 to boot, and then hit i to start the installer.
  10. On the Configure Console screen, select Accept these Settings.
  11. On the Select Task screen, select Quick/Easy Install.
  12. Under Are you SURE?, select OK. Wait a while.
  13. On the Install Kernel(s) screen, select Standard kernel.
  14. On the Reboot screen, select Reboot.
  15. While it’s rebooting, using the Devices | CD/DVD Devices menu at the top, select Remove disk from virtual drive. To speed booting, you can hit F1 and then 1 in the console. Then wait for pfSense to finish booting.

Edit the settings for the LiveCD VM, attaching the network adapter «Adapter 1» to the same internal network as the new pfSense VM (for example, pfS-SK). Then start the LiveCD VM, and download your OpenVPN configuration files for Linux from SecurityKISS. Don’t visit any other websites, to mitigate tracking risk. If necessary, you could also access your initial download (above) via shared folders, but that would require installing VirtualBox Guest Additions.

Freshly installed, pfSense routes all outbound connections (from computers on its LAN) through its WAN. But it blocks all new inbound connections from WAN, allowing only those that were established from LAN. If the LiveCD VM can’t see the Internet, recheck your host and the pfSense VM settings.

Configuring pfSense and Creating VPN Client

Now browse to the WebGUI at https://192.168.1.1 and create a server certificate exception. Login as admin with password pfsense, and complete the setup wizard. Decline the Gold support option, unless you have an anonymous credit/debit card. The next screen asks for DNS servers that pfSense should use internally, and whether to “[a]llow DNS servers to be overridden by DHCP/PPP on WAN”. I prefer to hard code DNS servers. Using DNS servers pushed by WAN can also be OK, but there are two risks. First, it may not work for some VPN combinations in nested VPN chains. Second, there is the risk that pfSense will end up using your ISP’s DNS servers (if they’ve been passed along to pfSense WAN). Even so, as long as you specify DNS servers in “Services: DHCP server”, the DNS servers that pfSense uses internally will not be pushed to DHCP clients (that is, your workspace VM, and other gateway VMs that connect through this one).

I recommend specifying reliable third-party DNS servers, such as those listed by WikiLeaks or JonDoNYM. If you’ve chosen the high-privacy option, you could specify DNS server(s) pushed by your direct-connect VPN service, or allow DNS servers to be overridden by DHCP on WAN. The key points are: 1) avoid using DNS servers pushed by your ISP; and 2) avoid using the same DNS servers at multiple levels of your VPN chain.

Accept the default timeserver and timezone, and hit Next. On the WAN screen, accept defaults, except for unchecking “Block private networks” and “Block bogon networks”, and hit Next. Accept all defaults on the LAN screen, and hit Next. Set a strong password on the next screen, and let pfSense reload. Now you’re at the pfSense WebGUI Dashboard. It’s best to reboot pfSense before proceeding. In the pfSense VM console window, reboot by entering 5 and then y to confirm.

Before creating an iVPN client, tweak pfSense settings. In “System: General Setup”, check “Do not use the DNS Forwarder as a DNS server for the firewall”, and save. That prevents propagation of DNS server specifications through pfSense. In the webGUI in “System: Advanced: Networking”, uncheck “Allow IPv6″ and check “Prefer to use IPv4 even if IPv6 is available”, and save. In “System: Advanced: Miscellaneous”, check “Skip rules when gateway is down”. That provides backup protection against leaks to WAN if the iVPN connection goes down. Now reboot pfSense again, from the console, by entering 5 and then y to confirm.

Although I have never seen outbound traffic use the WAN interface when a VPN is down, pfSense documentation does say this: “By default, when a rule has a specific gateway set and this gateway is down, a rule is created and traffic is sent to the default gateway. This option overrides that behavior and the rule is not created when gateway is down, so instead of flowing via the default gateway, the traffic will continue to attempt to use the gateway that is in a down state, and it will most likely not proceed. This is useful if you have traffic that should only ever use one specific WAN and never flow over any other WAN, regardless of how the firewall’s routing table has for the default route.”

For “normal” network setups, it’s important to specify good DNS servers, and to minimize the need for hard coding. In such cases, it’s best to allow system DNS servers to be overridden by DHCP/PPP on WAN, and to enable DNS forwarding. That allows DNS server specifications to transparently propagate through complex networks of pfSense routers. However, in nesting VPNs using pfSense VMs, it’s crucial to use different DNS servers at each level. Using the same DNS servers across levels would be a serious information leak.

Review the Setting Up VPN on Linux Workstation VM section of Basic Setup Using VMs, VPNs and Tor. Then, in the pfSense WebGUI Dashboard, go to System: Certificate Authority Manager. Add ca.crt in the CAs tab. If you have client.crt and client.key, add them in the Certificates tab.

Go to VPN: OpenVPN: Client and hit the + icon to create a client. The specifics depend on what the OpenVPN server supports, and what it expects from its clients. Use an OpenVPN configuration file (with extension .conf or .ovpn) from the service as a guide. In particular, note the server address and port, and the encryption algorithm. In chaining VPNs, it’s simpler to use IP addresses, rather than hostnames, although reliability may be lower (because you’ve broken failover for the VPN service).

For SecurityKISS, accept the defaults in VPN: OpenVPN: Client setup, except as noted:

Server host or address: 46.165.197.1 or 46.165.221.230 or 62.75.181.139 (Germany)
Server port: 123
Server host name resolution: enable (check) Infinitely resolve server
TLS Authentication: disable (uncheck) Enable authentication of TLS packets.
Client Certificate: client
Encryption algorithm: BF-CBC (128-bit)
Compression: enable (check) Compress tunnel packets using the LZO algorithm.
Advanced: remote-cert-tls server;verb 5

VPN services generally authenticate using either username and password, or client.crt and client.key. As noted above, SecurityKISS uses client.crt and client.key. But iVPN uses only username and password. A few VPN services use both. It’s unlikely that they would use no authentication.

If username and password are required, enter them under User Authentication Settings. For VPN services that use only username and password, such as iVPN, use “None (Username and Password required)” for “Client Certificate”. If there’s no authentication, instead use “webConfigurator default”.

Many services, such as IVPN, use TLS authentication with a shared key. Under TLS Authentication, leave Enable authentication of TLS packets. checked, but disable (uncheck) Automatically generate a shared TLS authentication key. Then paste ta.key in the text box.

For iVPN, enter the following in the Advanced box:

persist-tun;persist-key;persist-remote-ip;tls-cipher TLS-DHE-RSA-WITH-AES-256-CBC-SHA:TLS-DHE-DSS-WITH-AES-256-CBC-SHA:TLS-RSA-WITH-AES-256-CBC-SHA;ns-cert-type server;verify-x509-name de name-prefix

Save the client configuration, and check Status: OpenVPN. The status should be up. Then check Status: System logs: OpenVPN. You should see Initialization Sequence Completed near the bottom. A few lines above, you should see a line that starts (after the timestamp) with PUSH: Received control message …. If you don’t see redirect-gateway def1 in that line, edit the VPN: OpenVPN: Client setup, and add redirect-gateway def1; to the Advanced text box. If the VPN isn’t connecting, look for errors in Status: System logs: OpenVPN. You may need to tweak the Advanced string by adding other options from the service’s configuration file. If you see it complain about cipher mismatch, use the one it wants in your client configuration.

Once the VPN is connecting, check Status: System logs: OpenVPN again, find the PUSH: Received control message … line, and look for dhcp-option DNS server followed by an IP address. Then go to Services: DHCP server, and specify that IP address as DNS server. That works for most VPN services. But if it doesn’t, which you’ll discover soon, you’ll need to instead use third-party DNS servers, such as those from WikiLeaks or JonDoNYM. However, do not use any of the ones that you used above in the setup wizard (which appear in System: General Setup) because you don’t want to short-circuit VPN anonymity by using the same DNS server(s) for both entry and exit traffic.

At this point, pfSense is not routing anything through iVPN, and your LiveCD VM has no Internet connectivity. That’s normal. Don’t worry. Go to Interfaces: Assign network ports, and hit the + icon to add OPT1. Then go to Interfaces: OPT1, enable it, rename it as SKISS or whatever, save and apply changes. In Firewall: NAT: Outbound, select Manual Outbound NAT rule generation, save, and then apply changes. In the same tab, edit each of the four rules (two for localhost to WAN, and two for LAN to WAN). For each rule, click the e icon at the right, and use the toggle to change the Interface from “WAN” to SKISS (or whatever you’ve named it). Then hit the Apply Changes button.

In Firewall: Rules: LAN, edit the existing rule Default allow LAN to any rule. Using the Gateway toggle in the lower Advanced features section, select SKISS as gateway. Rename the rule as Allow LAN to any rule via SKISS and save. In the rule list, it should look like * LAN net * * * SKISS_VPNV4 none. Also edit the existing rule for IPv6 traffic. At the top, toggle Action from Pass to Block, and rename it as Block LAN IPv6 to any rule. Then apply changes.

Back in the pfSense VM console window, reboot by entering 5 and then y to confirm. After bootup, there should be an IP address after ovpnc1. If it shows NONE, hit enter once or twice. If it still shows NONE, recheck the pfSense configuration using the WebGUI. Start by looking for errors in Status: System logs: OpenVPN. It’s also possible that the direct-connect VPN connection has gone MIA. Check for that, and reconnect if necessary.

At this point, all outbound traffic from LAN will use the VPN gateway (SKISS or whatever) rather than the WAN gateway. Browse http://whatismyipaddress.com or another such site. The IP address should match the iVPN exit server for the route that you’re using. It may take a minute or two for the routing to stabilize.

There are two straightforward tweaks that help prevent leaks. First, in System: Routing: Gateways, edit the VPN gateway. Check Default Gateway to set, save, and then apply changes. Second, in System: General Setup, set the gateway for all DNS servers listed there as WAN. This is necessary because the VPN is now the default gateway. You might think that this setup would prevent the VPN link from coming up, but it doesn’t.

By default in pfSense, all outbound traffic is allowed on WAN. However, it is more secure to specify the hosts that pfSense can connect to via WAN, and to block everything else. This is rather more complicated, because one must use aliases. Using aliases in restricting outbound traffic on WAN is necessary because there can be multiple values, and because hosts may be specified by hostname, rather than by IP address. If this is your first pfSense setup, it’s best to verify that pfSense is working properly before attempting these steps.

Aliases are needed for four types of outbound traffic: 1) the DNS server IPs specified in “System: General Setup”; 2) the pfSense NTP server hostname specified in “System: General Setup”; 3) the OpenVPN server hostname or IP specified in “OpenVPN: Client”; and 4) the pfSense servers needed for updating. In Firewall: Aliases: IP, create four aliases, using the + button to add the values:

Name Values Description
dnssvr 1.2.3.4 5.6.7.8 … DNS server IP addresses
ntpsvr 0.pfsense.pool.ntp.org default pfSense NTP server
vpnsvr vpn.entry.server.net OpenVPN server hostnames or IP addresses
update www.pfsense.org updates.pfsense.org pfSense update server

Using these aliases, you then add rules for the WAN interface to pass necessary outbound traffic, and then a final rule to block everything else. In Firewall: Rules: WAN, create these rules, specifying “Single host or address” for the pass rules:

Action TCP/IP Version Protocol Source Port Destination Port Gateway Queue Description
pass IPv4 TCP/UDP WAN address * dnssvr * * none Allow to DNS server(s)
pass IPv4 UDP WAN address * ntpsvr * * none Allow to NTP server
pass IPv4 TCP/UDP WAN address * vpnsvr * * none Allow to OpenVPN server
pass IPv4 TCP/UDP WAN address * update * * none Allow to pfSense update server
block IPv4 * WAN address * * * * none Block all other IPv4
block IPv6 * WAN address * * * * none Block all IPv6

Then reboot from the console window, by entering 5 and then y to confirm.

Once the pfSense VPN-client VM is working properly, edit the settings for the workstation VM that will be using it. Attach its network adapter (“Adapter 1”) to the internal network that’s attached to the pfSense VM’s LAN adapter. Then start the workstation VM, and browse http://whatismyipaddress.com. The IP address should match the OpenVPN server that you’re using.

If the site doesn’t load, open a terminal and run ping 4.2.2.2. If you get no responses, recheck the VPN connection using the pfSense WebGUI. If Status: OpenVPN shows that it’s up, it’s probably DNS resolution that’s not working. Edit Services: DHCP server and specify reliable third-party DNS servers. But make sure not to use any of the DNS servers that you’re already using for the host machine, the direct-connect VPN, or pfSense itself (as specified in System: General Setup).

Next, check your DNS servers by running the standard DNS spoofability test at https://www.grc.com/dns/ in the workstation VM. It should report only the DNS server(s) that you have specified in pfSense under Services: DHCP server. If it reports others, there’s something wrong with the pfSense setup.

Leak Testing with Wireshark

After reviewing the section on installing and using Wireshark at the end of Basic Setup Using VMs, VPNs and Tor, install Wireshark and configure it on the workstation VM that you’re using. Then reboot the workstation VM. Also start the LiveCD VM. Both should be attached to the internal network that’s attached to the pfSense VM’s LAN adapter.

In testing for leaks, you’ll be capturing on the WAN interface in pfSense (using the WebGUI via the LiveCD VM), and also on eth0 in both the host machine and the workstation VM. If everything is working properly, you should see only traffic with the direct-connect VPN server on host eth0, and only traffic with the indirect-connect VPN server on pfSense WAN. On workstation eth0, you should see traffic with whatever websites that you use while testing.

In order to analyze the pfSense WAN capture with Wireshark, you’ll need to copy the capture file from the LiveCD VM to the host. And, in order to do that, you’ll need to (temporarily) install guest additions in the LiveCD VM, and create a temporary shared folder for the LiveCD VM, as explained in the Creating Diskless Linux LiveCD VM section of Installing VirtualBox and Creating Linux VMs. Alternatively, you can (temporarily) install and configure Wireshark in the LiveCD VM.

To begin the leak test, first go to Diagnostics: Packet Capture in the WebGUI for the pfSense VPN-client VM, which you’re accessing on the LiveCD VM. Accept the defaults for capturing on WAN, but specify 0 for Count (to set no limit). Then open Wireshark on both the host machine and workstation VM. You’ll be capturing on eth0 in both. Now start all three captures.

On the workstation VM, use Firefox to check http://whatismyipaddress.com, run the DNS test at https://www.grc.com/dns/, and browse for a while. After 10-20 minutes, stop all three captures, and save the pfSense capture on the LiveCD VM to the temporary shared folder on the host (unless you’re also running Wireshark in the LiveCD VM).

Run Statistics/Endpoints on all three captures, using Wireshark in the host (or LiveCD VM) for the pfSense capture. You should see only local IPs and the direct-connect VPN server on host eth0, only local IPs and the indirect-connect VPN server on pfSense WAN, and both local IPs and remote IPs used in testing on workstation eth0.

Now go to Diagnostics: Command prompt in the pfSense WebGUI that you’re accessing on the LiveCD VM. In the box under Execute Shell command, enter killall openvpn and hit Execute. Then start all three captures as explained above. Verify that Firefox on the workstation VM can’t see anything, and that pinging the IP address of your VPN server etc fails. After 10-20 minutes, stop all three captures, and save the pfSense capture on the LiveCD VM to the shared folder as above.

Run Statistics/Endpoints on all three captures. You should see only local IPs and the direct-connect VPN server on host eth0. On pfSense WAN, you should only see traffic with local IPs, and perhaps reconnection attempts from the indirect-connect VPN server that you were connected to. On workstation eth0, you should see only local IPs and connection attempts for whatever sites that you use while testing.

Finally, go to the pfSense console window, and reboot by hitting 5 and y. On the workstation VM, check http://whatismyipaddress.com to verify that it’s all working again.

That’s it.