pickaproxy.com blog

Paranoia part 2

Last Monday, Memorial Day in the US, and Victoria Day in Canada, I discovered a potentially troubling anomaly in the Tor network. Between about 10am and 3pm EST the number of computers running the Tor software as a relay or exit dropped to about 400 from the usual range of about 2,000.

This could be nothing serious, but also could be very serious in terms of increased exposure of Tor network traffic to possible monitoring. It is generally acknowledged that the more computers running the Tor software as relays and exits the greater anonymity of it's users. With 80% of the usual Tor servers flagged as out-of-service for 5 hours, this would mean all the normal Tor network traffic would be forced to travel through just 20% of the available servers.  In other words, if an imaginary adversary controlled 4 Tor servers, then instead of having access to just 0.2% of the total Tor network traffic (4 of 2,000), they could have access to 10% of the total Tor network traffic (4 of 400), as long as their 4 were part of the ones that remained in service.

How could all these servers have been flagged as out of service?  Was it an accidental anomaly in the Tor software?  Was someone maliciously manipulating the Tor "running" status flag for this time period, hoping that no one would notice?

We have no answers at this time, although we are convinced that this anomaly was not simply a problem with our own software which monitors the composition and state of the Tor network.  In response to this, we have started development of an alert system to be added to our pickaproxy.com service, so that when (if?) these conditions come up again, our users will be told, so they can make their own choices as to whether to continue using our service (and the Tor network in general) or disconnect until we issue a "Code Green" when more normal conditions return ...

Paranoia part 1

There are 5 very fast proxy servers operated by Performance Systems Inc. (PSI) in Washington, DC that scare me.

They are all exit nodes on the Tor network, providing proxy support for DNS (port 53), POP3 email (port 110), IMAP email (port 143), MSN Messenger (port 1863), ICQ (port 5190), Jabber and/or Google Talk and/or possibly a Tor Hidden Service (port 5222), MMCC (port 5050), Virtual Places (port 1533), and IRC (ports 6660-6667).  One of the 5 also provides proxy support for telnet (port 23).  None of them provide proxy support for http (port 80) or https (port 443), but there is a good chance if you are using the Tor network your traffic will run through 1 of these servers as a relay or guard/entry node.

None of them have any records in the DNS domain name system that I can find, they all have IP Addresses starting with 149.9.0, these are the only  proxy servers on the Tor network operated by PSI, and they all seem to be configured identically, even to the point of using the same out-of-date version of the Tor software.

I would say it is likely they are operated by, or on behalf of, some branch of the US government.

As a result, in order to limit your exposure to the potential of your internet activity being monitored by or through these servers, we have now configured our pickaproxy.com tryout services to always exclude these 5 proxy servers.  This will slow down our proxy service to some degree, but we consider the trade-off to be worth it.  Eventually we will allow our users to decide for themselves if they want to exclude these or any other proxy servers.

Comments are certainly welcome ...

News: SSL secure access to pickaproxy.com now available

One of the concerns with using pickaproxy.com as your proxy server is that the information you see in your browser, and that you send to web sites, can be monitored more easily than if you did not use a proxy server. The connection between your computer and our server is a single point of access, and if we were so inclined we could watch the content coming and going. This is true for much of the internet, and for any proxy server, and especially true in some countries such as those singled out by Reporters Without Borders (Reporters sans frontières) in their November 2005 article The 15 Enemies of the Internet.

We are not doing any such monitoring, first off, and have no plans to do so. But we are now offering a way for you to secure this data flowing between you and our server. This can be done by installing and configuring the open source "stunnel" software on your computer. stunnel has been available for many year, and works by using OpenSSL to encrypt all communication between your computer and our server. You then configure your "proxy" settings and your "stunnel" settings as follows:

• rather than "tryout.pickaproxy.com" and port "8123" you configure your proxy settings to be "localhost" and port "8100", and your stunnel settings to be "accept = 8100" and "connect = tryout.pickaproxy.com:7123"
• rather than "us.pickaproxy.com" and port "8125" you configure your proxy settings to be "localhost" and port "8100", and your stunnel settings to be "accept = 8100" and "connect = us.pickaproxy.com:7125"
• rather than "uk.pickaproxy.com" and port "8126" you configure your proxy as localhost port 8100, and your stunnel as accept = 8100 and connect = uk.pickaproxy.com:7126
• rather than "fr.pickaproxy.com" and port "8129" you configure your proxy as localhost port 8100, and your stunnel as accept = 8100 and connect = fr.pickaproxy.com:7129
• rather than "ru.pickaproxy.com" and port "8130" you configure your proxy as localhost port 8100, and your stunnel as accept = 8100 and connect = ru.pickaproxy.com:7130
• rather than "cn.pickaproxy.com" and port "8131" you configure your proxy as localhost port 8100, and your stunnel as accept = 8100 and connect = cn.pickaproxy.com:7131
• rather than "ca.pickaproxy.com" and port "8132" you configure your proxy as localhost port 8100, and your stunnel as accept = 8100 and connect = ca.pickaproxy.com:7132

stunnel is available for download from http://www.stunnel.org/download/binaries.html and at this time we are not providing support or assistance with installing or configuring stunnel, but we will eventually offer this service. I will say that stunnel configuration is not that difficult, and is done by making changes to the stunnel.conf file.