Anatomy of a BEC Scam

They typically land in no more than 25 inboxes in an organization — on a weekday first thing in the morning, posing as an urgent or time-sensitive email from a co-worker or executive. Business email compromise (BEC) scams represent just a small fraction of spear-phishing attacks overall, but these lucrative campaigns contain a few telltale traits.

Barracuda Networks analyzed the characteristics and trends of 1.5 million spear-phishing emails — of which just BEC made up just 7% — to determine the key methods scammers are using in their BEC campaigns. Don't let the tiny percentage fool you: BEC scams caused $26 billion in losses to businesses in the past four years, according to the FBI.

Some 91% of BEC attacks occur on weekdays, a tactic to blend in with the workday and appear more legitimate, the Barracuda study found. Attackers, on average, target up to six employees, and some 94.5% of all BEC attacks target less than 25 people in an organization. They do their homework on their targets, too, using real names of human resources, finance, and other executives as well as of the targeted employees.

The BEC emails often are written with a sense of urgency in order to rush the recipient into doing the attacker's bidding, with 85% marked as urgent, 59% requesting help, and 26% inquiring about availability, according to Barracuda's findings. And while users click on one in 10 spear-phishing emails, BEC emails are three times more likely to be opened. That doesn't necessarily mean the target fell for the message or followed the scammer's request, though, notes Asaf Cidon, a Barracuda adviser and professor of electrical engineering and computer science at Columbia University.

"We can't tell whether they went into a website and gave up their credentials," he says, or took other actions. The bottom line is when attackers impersonate someone in a position of authority or who appears legitimate, they get three times the click rate on the email, he says. 

Cidon says some attackers are making an extra effort to create very personalized messages, unlike mass phishing email campaigns. "BECs are probably going after larger amounts of money, not just trying to compromise single credentials. They are trying to extract a wire transfer out of an organization, [for example], so they are willing to do more research and spend more time" on their targets, he says.

Barracuda's study jibes with what other researchers have found in their BEC studies. "Successful BEC attacks are usually quite simple and mimic requests that could be reasonably expected to come from an employee’s executive or supervisor," notes Crane Hassold, head of Agari's cyber intelligence division.

He says wire transfer or payroll attacks usually target just one or two employees, typically in the finance or human resources department. But gift card BEC scams, where the attacker poses as a supervisor requesting the victim purchase and send him or her gift cards, often are sent to dozens of employees in an organization, he notes.

Barracuda saw the most BECs on Mondays, and Agari saw the most on Tuesdays (one out of four), with scams dwindling for the rest of the week. The emails most often arrive in the morning, with 9 a.m. as the bewitching hour since that's when most employees are first getting to their desks. Some 47% of BEC attacks are sent from Gmail accounts, and just 3% of BEC attacks come with a rigged URL or attachment. About 8% of BEC scams involve payroll requests, according to the security firm's report.

While most of the attacks originate from Nigeria, they now also come out of Ghana, Malaysia, and the United Arab Emirates, notes Agari's Hassold. 

The best way to beat back BECs: multifactor authentication to protect user credentials that get stolen and the usual mantra of educating users about the scams and how to spot one, including confirming an email address. Barracuda also recommends setting specific policies for financial transactions, banning email requests for any financial transactions, and adopting DMARC authentication, as well as machine learning technology, to protect the organization's domain from being spoofed.

But even with all of the best practices, there's no way to guarantee a user won't get duped by a BEC email. "There's no single silver bullet," Cidon says.

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