See What Nigerian Scammers Did To Themselves.


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A pair of security researchers recently
uncovered a Nigerian scammer ring
that they say operates a new kind of
attack called “wire-wire” after a few of
its members accidentally infected
themselves with their own malware. Over the past several months, they’ve
watched from a virtual front row seat
as members used this technique to
steal hundreds of thousands of dollars
from small and medium-sized
businesses worldwide. “We've gotten unprecedented insight
into the very nitty-gritty mechanics of
their entire operation,” says James
Bettke, a researcher at SecureWorks, a
subsidiary of Dell Inc. focused on
cybersecurity. Bettke and Joe Stewart, who directs malware research for
SecureWorks, are presenting the
details of their findings this week at
the annual Black Hat security
conference in Las Vegas.
This new type of attack is a twist on an old favorite. For years, rings of
scammers in West Africa have stolen
money from companies through a
technique known as "Business Email
Compromise," or BEC, in which they
use internal corporate email accounts to execute fraudulent financial
transactions. Or, in another approach
known as “spoofing,” scammers have
impersonated a CEO’s email from an
external account to persuade an
employee to send a wire transfer to their own bank account.
The SecureWorks experts say wire-
wire, which is how criminals refer to
the new type of attack, represents a
more sophisticated approach to BEC
that is harder to detect. Bettke and Stewart discovered the ring in
February when five of the scammers
self-infected their own computers with
the same malware they were using to
steal from others. Such errors are a
surprisingly common way for security researchers to get an inside look at
scammers’ operations.
For months, the malware automatically
loaded screenshots and keystrokes
from compromised computers to an
open web database. One of the infected scammers also frequently
trained new scammers, which
revealed even more details about their
techniques. The SecureWorks team
initially found the database by using
the virus scanning tool VirusTotal to search for suspicious email
attachments.
The wire-wire scammers begin by
using a simple marketing tool to
scrape the email addresses of
businesses and employees from corporate websites. Then, they blast
these addresses with messages
containing keylogger software or
other malware in a process called
“bombing.” Employees who click on a
malicious link or open an infected attachment might be prompted to log
in, providing scammers with the
password to their email accounts.
Once they’re in, the scammers allow
the employee to continue with
business as usual and discreetly monitor the account for potential
financial transactions. As soon as they
see that the employee is sending an
invoice to a customer, they reroute it
through their own email account and
physically alter the account number and routing number before
forwarding it on to the customer. The
email address they use is often very
similar to the original email address, so
it’s easy to miss. Unlike spoofing, BEC
techniques such as wire-wire rely on earning internal account access rather
than externally impersonating a
company account.
Since February, the SecureWorks team
has witnessed the thieves deploy this
method to reroute transactions averaging between US $30,000 and $
60,000 from mostly small and
medium-sized businesses making
international deals. In one case, the
attackers rerouted a $400,000
payment from a U.S. chemical company to its Indian supplier.
Bettke and Stewart estimate the group
they studied has at least 30 members
and is likely earning a total of about $3
million a year from the thefts. The
scammers appear to be "family men" in their late 20s to 40s who are well-
respected, church-going figures in
their communities. “They're increasing
the economic potential of the region
they're living in by doing this, and I
think they feel somewhat of a duty to do this,” Stewart says.
After the fact, it can take awhile before
the customer and seller realize they’ve
been scammed—often, neither buyer
or seller realizes that something is
amiss until the shipment or payment is overdue. Given their vantage point,
Stewart and Bettke have tried to alert
some businesses to the scam before
the fraudulent transactions are
complete, but they sometimes have a
hard time persuading employees that they aren’t scammers themselves.
The SecureWorks team has notified
Nigeria’s Economic and Financial
Crimes Commission and their
description of wire-wire scamming has
led to at least one active investigation. They say the easiest way for business
owners to prevent such attacks is to
require two-step verification for
employee logins. Stewart and Bettke
have also uploaded a program to
GitHub that detects digital artifacts that remain on an altered invoice to tip
employees off to suspicious activity.