Doppelganger Danger

How one small dot—if part of a typosquat—can lead to security breach

• By Ronnie Rittenberry
• Jan 01, 2012

In the world of literature, folklore and myth, the appearance of a doppelganger is generally bad news. Often depicted as ghostly doubles (and literally meaning “double walkers” in German), doppelgangers usually portend illness, danger or even death when they show up in stories. Well, now the same is pretty much true when they surface in the world of e-commerce.

Doppelganger domains, as they’ve been dubbed, are domains whose names are nearly identical to those of legitimate companies except the doppelganger version—registered for presumably nefarious purposes— is strategically missing the dot that separates the legitimate version’s subdomain from the domain. For example, “ussecurity.com” would be a doppelganger for “us.security.com.” E-mails intended for the latter domain but sent without the initial dot would be routed to the doppelganger site, potentially for malicious use. Cyberthieves deploying the doppelganger site could then cover the misdirection by redirecting the original e-mail to the legitimate domain.

At the same time, the doppelganging ne’er-dowells could also send out e-mails from their bogus domains and hope that some recipients wouldn’t notice the missing dot and open the e-mail. Malware could ensue.

Squatter’s Rights?

Now, from one angle, doppelganger domains are merely variations on a theme that has been playing on the Internet for about as long as e-commerce has been around. They are forms of the larger general practice known as “typosquatting,” or URL hijacking, which relies on the same principle of exploitation whereby cyberthieves register domains with names that are deliberately very close-sounding to legitimate names in hopes that users will unwittingly arrive at the squatted site by virtue of making a typo when entering the Web address.

Usually, the variance in the squatted domain name is the absence or presence of a single letter (“yuube. com” instead of “youtube.com,” for example) or a different top-level domain (“us.security.org” as opposed to “us.security.com”). With the availability of generic top-level domains set to expand this year (and, given the necessary approval process, to actually start appearing in 2013), the opportunities for mistakes and malefaction associated with this ploy are likely to increase. The only thing making doppelganger domains distinct from other forms of cybersquatting is the absence of their one tiny, potentially easy-to-miss, subdomain-dividing dot.

Researchers at Godai Group, a San Franciscobased “information security think tank,” coined the term for the new breed of hacking misdeed in their recently issued white paper on the subject (found at http://godaigroup.net). In the paper, they note that doppelganger domains “have a potent impact via email as attackers could gather information such as trade secrets, user names and passwords, and other employee information.”

To prove their point, the researchers profiled every Fortune 500 company and found 151 of them (or 30 percent) vulnerable to doppelganger domain danger. By industry, specialty retailers were the most susceptible to the fraud, followed closely by commercial banks and telecommunications companies.

During its research, the group found that some doppelganger domains for the companies had already been registered to locations in China and to domains associated with malware and phishing. According to the report, “While it is unknown if these domains are used in a malicious fashion, it is apparent that some targeting is happening here.”

Further, the group set up 30 doppelganger accounts itself for various firms just to see what would happen. After a six-month test period, the accounts had attracted 120,000 e-mails amounting to 20 gigabytes of data, including potentially valuable information such as contracts, invoices, reports, network diagrams and more.

“Twenty gigs of data is a lot of data in six months of really doing nothing,” said senior researcher Peter Kim to Wired. “And nobody knows this is happening.”

Doppel Jeopardy

The Godai Group recommends several steps for mitigating doppelganger danger, including purchasing and registering any conceivable doppelganger domain; internally configuring Domain Name System (DNS) servers to not resolve any doppelganger domains (which would protect internal-only e-mail from being accidentally sent to one); and identifying if attackers are already using a doppelganger domain against your company and, if so, filing a Uniform Domain Dispute Resolution Policy (UDRP) against them with the Internet Corporation for Assigned Names and Numbers (ICANN).

The obvious challenge of trying to proactively buy up the doppelganger domains is that the number of potential mistypings of a particular URL is not necessarily fathomable, making it at the very least difficult to acquire all of them so that a company would not be vulnerable to this type of hacktivity.

For smaller companies, the time and expense of preventing such potential typo-oriented security breaches could be a factor and call into question how significant a threat this type of attack really is. After all, according to the Godai Group’s own results, most companies—70 percent, in fact—were not deemed susceptible to doppelganger jeopardy. Nevertheless, the group noted that while its research focused on Fortune 500 companies, the vulnerability could exist for any organization that uses subdomains.

The group notes in the paper that it does free domain scanning to determine doppelganger susceptibility. For more information, visit http://godaigroup. net/free-doppelganger-domain-scan/.

This article originally appeared in the January 2012 issue of Security Today.