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Typo-squatting domains can harvest corporate emails

Executive butterfingers get slurped by honeypots

Typo-squatting domains might easily be used to intercept misdirected corporate emails, according to new research.

Domain typo‐squatting has long been used as a means to expose butter-fingered users who accidentally misspell a legitimate domain to malware. So-called doppelganger domains take advantage of an omission instead of a misspelling, for example missing the dot between host/subdomain and domain.

Security researchers at Godai Group profiled companies in the Fortune 500 for susceptibility to attacks based on this ruse, and found that 151 (30 per cent) were vulnerable.

Doppelganger domains open up the possibility of two types of attack. Attackers could passively set up email honey pots on such domains and wait for mistyped emails to arrive. In this scenario, attackers would configure their email server to vacuum up all email addressed to that domain, regardless of the user it was sent towards. Such catch-all email addresses would pick up email from both internal and external users.

The second type of attack would rely on actively trying to trick a targeted individual or group of individuals into sending email to doppelganger domains. Attackers would typically run the scam by posing as workers in the same company or their business associates. Purchasing doppelganger domains for both a targeted conglomerate and its business partners or bank creates a possible means to run man-in-the-middle (or Man‐in‐the‐MailBox) attacks, the researchers warn.

As an experiment, Godai Group registered doppelganger domains for Fortune 500 firms before passively collecting emails sent to mistyped domains. During a six‐month period, they collected more than 120,000 individual emails (or 20 gigabytes of data). All sorts of sensitive information appeared in this batch including trade secrets, business invoices, personal information of employees, network diagrams, usernames and passwords, etc. All the original data that was collected during the research period has been deleted.

"Essentially, a simple mistype of the destination domain could send anything that is sent over email to an unintended destination," the GodaiGroup researchers explain.

Although this was outside the scope of the study, the team also noticed network service requests being sent to doppelganger domains. This means that by setting up a fake SSH server, for example, it would be possible to harvest remote access usernames and passwords.

After reviewing the WHOIS information from all Fortune 500 companies, Godai Group noticed of the many hi-tech firms had doppelganger domains registered to locations in China. Many of these domains are already associated with malware and phishing, it warns.

Godai Group suggests a series of steps firms can take to address the security risk posed by doppelganger domains. Corporates can purchase such domains or, if they have already been registered, file a domain registration dispute. Alternatively internal users can be prevented from sending mistyped emails to doppelganger domains by either configuring internal DNS not to resolve doppelganger domains or configuring email servers not to send messages to such domains.

More details of the group's research on doppelganger domains – as well as details of its suggested mitigation tactics – can be found here (7-page/566KB PDF). ®

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