Is it possible to locate Tor/proxy users? Spam is getting on my nerves

Question

I'm managing a huge forum (over 15k posts and 500 users) and lately some guy uses a VPN (probably) to spam my forums with topics such as: "LOLOLOLOLOLOLOLOL"

Now, I'm pretty sure he's using Tor or a proxy, the IP and the countries are always changing but the posts have the same pattern - it is the same guy. However, I can't seem to find a way to identify him. I am willing to take it seriously as a criminal case.

The guy created over 40 spam accounts and posted over 250 topics and posts with spam.

Here are some posts from whois:

 - http://puu.sh/2cZRJ - data
 - http://puu.sh/2cZS4 - whois
 ___
 - http://puu.sh/2cZOZ - data
 - http://puu.sh/2cZP8 - whois
 ___
 - http://puu.sh/2cZPZ - data
 - http://puu.sh/2cZQb - whois
 ___
 - http://puu.sh/2cZQX - data
 - http://puu.sh/2cZQr - whois
 ___
 - http://puu.sh/2cZSm - data
 - http://puu.sh/2cZSF - whois
 ___
 - http://puu.sh/2cZTh - data
 - http://puu.sh/2cZT2 - whois
 ___
 - http://puu.sh/2cZTK - data
 - http://puu.sh/2cZTY - whois

And loads more, but the list won't end. How can I identify the user?

Answer 1

Your forum accepts posts from anybody. That is your core problem. Connecting to your site from various IP throughout the world is trivial, if only by using Tor. Tor provides "high anonymity" in that not only the user's identity is hidden, but each request is anonymous -- you cannot, from the outside, make sure whether two distinct requests are from the same human user or not.

This can be fixed at two levels:

1. Restricted anonymity: enforce user registration and authentication. Users may use a pseudonym, and need not provide an email address or any other identification, but your forum will insist on a login process before posting. That way, you can know whether two comments come from the same person. Note that this does not totally solve the issue; instead, that moves it to the registration process. The poor sob who has nothing better to do with his time than defacing your forum will adapt and engage into mass registration of phony accounts.

2. No anonymity (with regards to you): user registration, this time with an email address, which is verified during registration (you make sure that the registrant can read an email sent at the address he provided). The possibility to be identified, if only by law enforcement agencies, could be a powerful deterrent for wannabe spammers (even if the said spam is not necessarily punished by Law: to my constant dismay, there is no law against writing "LOLOLOLOL").

If you choose to retain anonymous posting, then, well, welcome to the wonderful world of Mankind. While most humans are civilized, honest and polite, there is always one user who thinks exposing his lack of education is a smart thing to do. The best you could do, then, is to patiently clean up (possibly proactively, by enforcing pre-publication control of all posts by trusted moderators) until the perpetrator loses interest or reaches the age of 14, whichever comes first. This may take a few weeks or months.

Historically, most societies have dealt with troublemakers by a mixture of ostracism and actual penalties (up to and including death). The apparent anonymity of Internet prevents efficient penalties (with a lot of resources, this anonymity can usually be unraveled, but police forces will not do that until an actual crime is committed). Ostracism is social pressure, so it does not work on people who do not feel the target forum as being a "society" they are part of.

Answer 2

I strongly believe that the user is using Tor and possibly other services to anonymize their transmissions. At least two of the IP addresses you mentioned are Tor exit nodes. The points which Thomas Pornin laid out in his answer are the best solution, and are what I would do if I were you. Registration and user reputation are proven ways to alleviate spam. Just look at Stack Exchange for a great example.

You may wish to read The Tor Abuse FAQ for more information. It clearly describes that They are technically unable to identify this user:

There is nothing the Tor developers can do to trace Tor users. The same protections that keep bad people from breaking Tor's anonymity also prevent us from figuring out what's going on.

As a last resort, you could try blocking all Tor users from accessing your site. But as described there, I think that's a very poor solution to the problem:

Second, consider that hundreds of thousands of people use Tor every day simply for good data hygiene — for example, to protect against data-gathering advertising companies while going about their normal activities. Others use Tor because it's their only way to get past restrictive local firewalls. Some Tor users may be legitimately connecting to your service right now to carry on normal activities. You need to decide whether banning the Tor network is worth losing the contributions of these users, as well as potential future legitimate users. (Often people don't have a good measure of how many polite Tor users are connecting to their service — you never notice them until there's an impolite one.)

If you do still want to block all Tor users, the specific implementation will depend on your software.

Answer 3

Why don't you to restrict access to certain privileges based upon community rating system e.g 500 hours of site work to post threads etc. Effectively ban users with consecutive 10 negative feedback

Second you can put all new users post on hold for review then submit it.

As for filtering tor you can block on all exit nodes addresses they are available publicly.

Answer 4

You're running a forum, can you say if its custom or what forum software it is?

One way to control this is that it may be possible to check if an IP is a Tor exit node. Have your forum software check an anonymous posters IP against a list of known exit nodes, if it is you can decide to block or show a CAPTCHA.

I think in this case it would be better to treat this as a spam problem rather than a Tor problem. You have a user spamming your forum quite easily, a 'legitimate' spammer selling Vi@gr@ can get in too. If you control your spam problem you deal with your troll and any potential spammers.

Answer 5

You can email the VPN provider, mention the abuse and request a take down of the account. You can also ask to get the relevant personal data. The problem is they do not have the answer you in any way.

If it's really annoying file a complaint at your local police office, chance are unfortunately rather high that they won't (be able to) do anything about it either.

Now without identifying you can start by just blocking the IPs of the VPN provider.

EDIT

Since you are being visited through Tor there is not much you can actually do. You should try to implement the suggestion done by Thomas Pornin and restrict anonymity.