The comforts of home can lead even the most disciplined executives to let their guards down when accessing work data through the Internet—to the delight of hackers and thieves.

Cyber attacks on small business executives are up, with criminals gaining much of their booty through personal and business communications conducted over wireless broadband networks, security specialists say.

While the proliferation of wireless Internet access has been a boon for business productivity, it has also been a gift to hackers who prey upon those who access these networks carelessly.

“Hackers love it,” David W. Stender, enterprise security officer at M&T Bank, said of the widespread use of wireless Internet. He was speaking at a press briefing held by Wilmington Trust Corp., which is owned by M&T.

“When we all used dial-up connectivity, the speeds were too slow to make attacking home systems easy,” Stender said in an e-mail afterward. “It also meant you could only attack when users were online. Nowadays, everyone has cable or DSL or FIOS or other fast home connections and they never turn them off. That makes attacking very convenient for hackers.”

Such criminal activity should get the attention of those who handle the data of high-net-worth clients—particularly if they access client data from home or on the road through a smart phone, tablet or laptop.

Business E-mail Compromise (BEC) crimes against businesses have resulted in losses of $3 billion globally over the past three years, according to the FBI. Nearly a third of the losses came at the expense of U.S. companies.

Stender says 80 percent to 90 percent of his clients who are hacked are victimized through wire transfers. In a typical scenario, a hacker will gain access to an account and use that access to put in a wire transfer request. The account access is usually accomplished through a hack or a “spoof” that involves tricking an employee into granting account access, according to the FBI.

One tactic that is being used more frequently is executive impersonation, where hackers hack into a company e-mail account and pose as a senior executive in need of a wire transfer. M&T Bank has more information on that tactic and how to prevent it here.

In 2015, 43 percent of cyber attacks targeted small business, compared to just 18 percent in 2011, according to the software security firm Symantec.