A group of scammers has been abusing a Gmail feature that gives users control over all dotted versions of their Gmail addresses.
The feature, Agari says, has provided scammers with the ability to scale their operations by opening multiple fraudulent credit card accounts. These accounts are then used to file for fraudulent unemployment benefits, file fake tax returns, and bypass trial periods for online information providers.
One scammer was reportedly able to submit a total of twenty-two separate applications under different identities, which allowed them to open over $65,000 in fraudulent credit cards at a single financial institution.
The fraudulent operations were possible because Gmail interprets email addresses without dots (.), regardless of where in the email address or how many dots are used. Basically, it sees bad.guy[at]gmail.com as badguy[at]gmail.com, and the same applies to b.a.d.g.u.y[at]gmail.com and to other variations.
As a security researcher pointed out last year, however, this so called feature can be abused in scams that use real email addresses and come from legitimate senders. The issue is that all dot variants of a Gmail account direct all emails to the same inbox. Other service providers, however, treat each address variant as a separate account.
Agari discovered that cybercriminals were able to scale such operations more efficiently, by creating multiple accounts on a website and directing all communication to a single Gmail account. Thus, they would no longer need to create and monitor a different email address for each account on a website.
Starting in early 2018, a group of actors engaged into an extensive use of Gmail dot accounts to commit a variety of fraudulent activities, such as submitting 48 credit card applications at four financial institutions in the United States (at least $65,000 in fraudulent credit was approved).
They also registered 14 trial accounts with a commercial sales leads service to collect targeting data for BEC attacks, filed 13 fraudulent tax returns with an online tax filing service, submitted 12 change of address requests with the US Postal Service and 11 fraudulent Social Security benefit applications, applied for unemployment benefits under nine identities, and submitted applications for FEMA disaster assistance under three identities.
“In each case, the scammers created multiple accounts on each website within a short period of time, modifying the placement of periods in the email address for each account. Each of these accounts is associated with a different stolen identity, but all email from these services are received by the same Gmail account,” Agari explains.
This allowed the actors to centralize and organize their activity around a small set of email accounts, which increased the efficiency of their attacks. The group used a total of 56 different dot variants of a single Gmail email address for their fraudulent operations, Agari says.