When we set up TOR infrastructure at USU, we looked at the costs and benefits.
There are definite costs to running TOR infrastructure. You have to be aware of them. Some of the costs can be mitigated, but some can't. At the end, you have to be able to show that the benefits outweigh the costs.
First we examined the benefit. We made a clear statement of the benefit. It is:
USU has many researchers and students who deal in sensitive subjects such as Climate Change, Reproductive Issues, Political Systems, Animal Research, etc.. These students and researchers frequently need privacy and security to advance the goals of USU.
Then we discussed the various costs and methods of mitigating the costs. Afterwards, we decided that the costs could be made acceptable, if we were careful.
- Our cost mitigation strategy had several parts:
- 1) We arranged for the TOR infrastructure to have an academic sponsor. The USU CS department agreed to sponsor the TOR project. This gave us an existing structure for providing IT support. And, frankly, TOR is easier to support than some of the other academic projects.
- 2) Most of the direct costs of creating and administering the TOR infrastructure are born by the USU CS department. It really helps that their admin is a diligent and responsible admin. It has been a joy to work with him.
- 3) We have tried to put all the TOR infrastructure on a small CIDR. If people need to block TOR, we try to make it easy for them to block it without effecting other things. That said, if I had to do it again, I think I would continue to have the TOR entry nodes and intermediate relays on a small USU CIDR. I think I would ask USU's ISP (UEN) for a small /28 and hook it up external to USU's normal security perimeter. Then I would put the TOR exit nodes on that external CIDR. This makes it easier to set routing and firewall policy. It also enables entering the TOR switching network internal to USU.
- 4) We examined the TOR traffic and tried to minimize the abusive bits. In our case, we found that most of the TOR web browsing looked non-abusive. However, the majority of the SSH and RDP traffic looked abusive. So, we asked the TOR admin to limit those protocols.
- 5) We clearly documented our TOR setup and use. The TOR nodes have meaningful hostnames. The systems have are well defined roles and responsibilities. We have strongly discouraged the TOR admin from using those systems for anything else.
- 6) We created processes for dealing with the abuse reports.
Here is our standard response to an abuse report against USU's TOR infrastructure:
=BEGIN ABUSE RESPONSE=
The activity that you have reported is being emitted by a TOR exit node:
$ host 126.96.36.199
188.8.131.52.in-addr.arpa domain name pointer tor-exit-node.cs.usu.edu.
$ host 184.108.40.206
220.127.116.11.in-addr.arpa domain name pointer tor-exit-node-2.cs.usu.edu.
This TOR node is a project of USU's CS department. USU has many researchers and students who deal in sensitive subjects such as Climate Change, Reproductive Issues, Political Systems, Animal Research, etc.. These students and researchers frequently need privacy and security to advance the goals of USU.
Almost all TOR traffic is generated by innocent people who are attempting to escape the shadow of a totalitarian government. But, unfortunately, sometimes criminals attempt to use TOR to attack others.
We are in discussion with our TOR admins to try to find ways to limit the attack activity. Of course, this rapidly becomes a sticky issue. If we start inspecting and censoring some of the TOR activity, then we have less of a defense when we get pressure to inspect and block the rest. And, even starting down this path may make us legally liable for ALL the TOR traffic. Our best action may be to keep our hands off and observe strict network neutrality.
We are still pondering our options.
Please accept our apologies in the mean time.
USU IT Security
=END ABUSE RESPONSE=