Tools to identify anonymous users online

Corporate investigator Brandon Gregg explains how online services and tools can help crack a case

After posting 5 Free Ways to Track Online Leaks of Information, I received numerous requests asking how to identify the online source leaking the confidential company information. Here are some techniques a corporate investigator can use to identify anonymous users online.

In most cases the crooked insider is doing one of three methods: Posting to an online message board (i.e. Yahoo Finance Board), creating a URL along the lines of, or emailing your company, clients and competitors. In all three scenarios it is also likely that he or she is using a [fake and anonymous email address that does not identify them outright (i.e., rather than Luckily for us, most insiders are still failing to hide their IP address even within their "anonymous" email. Once you have that address you can lookup basic information at

Although Internet Service Providers diligently project the identities of their users (unless you have a court subpoena), using some of these tricks during regular office hours may pull your insider into one of the many traps below while at work. Even a fake Gmail account used on the insider's company network will show the company IP address that your IT department can legally pinpoint to the user.

First, confirm if the email is a randomly created address. Using Intelius' reverse email lookup, you can confirm (for free) whether the address belongs to anyone. If the email is registered to a name, you can pay a fee of $4.95 and close your investigation.

A powerful second tool is Register for the website and search the insider's email address. The service it will do a deep web search of multiple blogs, social networking sites, and photo sharing websites, and even confirm the email address is active. I cannot tell you how many times this website has closed my investigations. Often the insider uses a random, old email address that he or she hasn't used in years and Spokeo tracks it back to a Flickr photo of them-case closed.

After you have identified that the insider's email address is a freshly created, anonymous account, there are two options to get their IP address. A) Convince them to email you directly and identify the IP address in the received header or this quick email IP tool, or B) sign up for and email the insider. Even if the insider only opens up your convincing email (RE: I Know Who You Are), read notify will automatically and covertly send back a snapshot of the reader's IP address, the date and time the message was opened, location of recipient (per their ISP city /town), map of location, apparent email address of opening (if available), referrer details (ie; if accessed via web mail etc), URL clicks, how long the email was read for, how many times your email was opened and if your email was forwarded, or opened on a different computer. If this is done during office hours and your insider likes to check their email at work, you got them.

If the user is unreachable by email, you can also create your own simple webpage using one of the millions of free webpage accounts online and a free basic counter that collects user information, such as Simply paste the link on the insider's message board and let users click it. Stat Counter will then collect IP information, one of which could be your insider surfing while at work.

These tricks are great if you can identify the user with the IP address, but sometimes the address comes back to a personal ISP, or the user actually is using a proxy or TOR, so you're at square one. In those cases a little social engineering is needed to convince the user to post or send you a document, pdf or any other file that has hidden metadata. Opening the file and looking at the properties may give you the author's name, employee ID or that one clue that will identify them. The key is to be creative and get the insider to show you a glimpse of who they are. One piece of information can take them tumbling down and close your investigation.

-Brandon Gregg is a corporate investigations manager.

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