Tuesday, September 21, 2010

Using the 'net

Using the 'net
All of this seems like a lot of trouble. Is there not an easier way of becoming anonymous on the Internet? Indeed there are many ways to skin a cat. It really depends on what type of connectivity you need. Lets assume all you want to do is sending anonymous email (I look at email specifically because many of the techniques involved can be used for other services such as HTTP, FTP etc.). How difficult could it be?
For many individuals it seems that registering a fake Hotmail, Yahoo etc. account and popping a flame email to a unsuspected recipient is the way to go. Doing this could land you in a lot of trouble. Lets look at a header of email that originating from Yahoo:
Return-Path:
Received: from web111.yahoomail.com (web111.yahoomail.com [205.180.60.81])
by wips.sensepost.com (8.9.3/1.0.0) with SMTP id MAA04124
for ; Sat, 15 Jul 2000 12:35:55 +0200 (SAST)
(envelope-from r_h@yahoo.com)
Received: (qmail 636 invoked by uid 60001); 15 Jul 2000 10:37:15 -0000
Message-ID: <20000715103715.635.qmail@web111.yahoomail.com>
Received: from [196.34.250.7] by web111.yahoomail.com; Sat,
15 Jul 2000 03:37:15 PDT
Date: Sat, 15 Jul 2000 03:37:15 -0700 (PDT)
From: RH
Subject: Hello
To: roelof@sensepost.com
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
The mail header tells us that our mailserver (wips.sensepost.com) received email via SMTP from the web-enabled mailserver (web111.yahoomail.com). It also tells us that the web-enabled mailserver received the mail via HTTP (the web) from the IP number 196.34.250.7. It is thus possible to trace the email to the originator. Given the fact that we have the time the webserver received the mail (over the web) and the source IP, we can use techniques explained earlier to find the person who was sending the email. Most free web enabled email services includes the client source IP (list of free email providers at www.fepg.net).
How to overcome this? There are some people that think that one should be allowed to surf the Internet totally anonymous. An example of these people is Anonymizer.com (www.anonymizer.com). Anonymizer.com allows you to enter a URL into a text box. It then proxy all connections to the specified destination. Anonymizer claims that they only keep hashes (one way encryption, cannot be reversed) of logs. According to documentation on the Anonymizer website there is no way that even they can determine your source IP. Surfing to Hotmail via Anonymizer thus change the IP address in the mail header.
But beware. Many ISPs make use of technology called transparent proxy servers. These servers is normally located between the ISP's clients and their main feed to the Internet. These servers pick up on HTTP requests, change the source IP to their own IP and does the reverse upon receiving the return packet. All of this is totally transparent to the end user - therefor the name. And the servers keep logs. Typically the servers cannot keep logs forever, but the ISP could be backing up logs for analyses. Would I be tasked to find a person that sent mail via Hotmail and Anonymizer I would ask for the transparent proxy logs for the time the user was connected to the web-enabled mailserver, and search for connections to Anonymizer. With any luck it would be the only connections to the Anonymizer in that time frame. Although I won't be able to prove it, I would find the source IP involved.
Another way of tackling the problem is anonymous remailers. These mailservers will change your source IP, your field and might relay the mail with a random delay. In many cases these remailers are daisy chained together in a random pattern. The problem with remailers is that many of them do keep logs of incoming connections. Choosing the initial remailer can be become an art. Remailers usually have to provide logfiles at the request of the local government. The country of origin of the remailer is thus very important as cyberlaw differs from country to country. A good summary of remailers (complete with listings of remailers can be found at www.cs.berkeley.edu/~raph/remailer-list.html).
Yet another way is to make use of servers that provide free Unix shell accounts. You can telnet directly to these servers (some provide SSH (encrypted shells) access as well). Most of the free shell providers also provide email facilities, but limit shell capabilities -e.g. you can't telnet from the free shell server to another server. In 99% of the cases connections are logged, and logs are kept in backup. A website that list most free shell providers are to be found at www.leftfoot.com/freeshells.html. Some freeshell servers provider more shell functionality than others - consult the list for detailed descriptions.
How do we combine all of the above to send email anonymously? Consider this - I SSH to a freeshell server. I therefor bypass the transparent proxies, and my communication to the server is encrypted and thus invisible to people that might be sniffing my network (locally or anywhere). I use lynx (a text based web browser) to connect to an Anonymizer service. From the Anonymizer I connect to a free email service. I might also consider a remailer located somewhere in Finland. 100% safe?
Even when using all of above measures I cannot be 100% sure that I cannot be traced. In most cases logs are kept of every move you make. Daisy chaining and hopping between sites and servers does make it hard to be traced, but not impossible.
Other techniques
1. The cybercafe is your friend! Although cybercafes are stepping up their security measures it is still relatively easy to walk into a cybercafe without any form of identification. Sit down, and surf to hotmail.com - no one would notice as everyone else is doing exactly the same thing. Compose your email and walk out. Do not become a regular! Never visit the scene of the crime again. When indulging in other activities such as telnetting to servers or doing a full blast hack cybercafes should be avoided as your activity can raise suspicion with the administrators.
2. Search for proxy like services. Here I am referring to things like WinGate servers. WinGate server runs on a Microsoft platform and is used as a proxy server for a small network (read SOHO environment with a dial-up link). In many cases these servers are not configured correctly and will allow anyone to proxy/relay via them. These servers do not keep any logs by default. Hoping via WinGate servers is so popular that lists of active WinGates are published (www.cyberarmy.com/lists/wingate/).
3. With some experience you can hop via open routers. Finding open routers are very easy - many routers on the Internet is configured with default passwords (list of default passwords to be found at www.nerdnet.com/security/index.php )Doing a host scan with port 23 (later more on this) in a "router subnet" would quickly reveal valid candidates. In most of the cases these routers are not configured to log incoming connections, and provides excellent stepping-stones to freeshell servers. You might also consider daisy chaining them together for maximum protection.
4. Change the communication medium. Connect to a X.25 pad via a XXX service. Find the DTE of a dial-out X.25 PAD. Dial back to your local service provider. Your telephone call now originates from e.g. Sweden. Confused? See the section on X.25 hacking later in the document. The exact same principle can be applied using open routers (see point 3) Some open routers listens on high ports (typically 2001,3001,X001) and drops you directly into the AT command set of a dial-out modems. Get creative.
The best way to stay anonymous and untraceable on the Internet would be a creative mix of all of the above-mentioned techniques. There is no easy way to be 100% sure all of the time that you are not traceable. The nature of the "hack" should determine how many "stealth" techniques should be used. Doing a simple portscan to a university in Mexico should not dictate that you use 15 hops and 5 different mediums.

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