An epidemic of hacking and ransomware is bringing misery to computer users everywhere. But for cybersecurity firms like Wandera, the computer crisis has brought a boatload of business and investment.
Wandera, founded in London in 2012, specializes in enterprise mobile security—meaning it helps big companies keep hackers from breaking into corporate networks through the growing number or apps and mobile devices their employees use.
On Thursday, the company announced it has raised a $27 million Series C funding round, led by Sapphire Ventures with participation from existing investors Bessemer Venture Partners and 83North.
The new money, which brings Wandera’s funding to date to $50 million, comes as the company claims it is in the midst of a torrid growth spree. Wandera says its customer base amid Fortune 500 companies has grown five-fold, and its bookings have increased 250% year-over-year.
In an interview with Fortune, CEO Roy Tuvey said Wandera’s mobile security service takes two approaches. The first is to detect attacks and help companies lock down sensitive data that can be accessed through devices.
Get Data Sheet, Fortune’s technology newsletter.
The second and more recent approach consists of screening for behavior that could lead to cybersecurity trouble in the first place. Specifically, companies can ask Wandera to monitor employees’ use of corporate devices to visit risky websites, such as porn sites, or do things like use the devices to access personal Dropbox accounts.
Tuvey added that an emerging threat for companies is phishing aimed at mobile devices, where the small screen can make it harder for users to detect bad actors.
Wandera plans to use the new funding to invest in R&D and data science operations in London and Israel. Tuvey add that mobile security is costly because it involves designing tools for a wide variety of mobile platforms.
Tuvey did not disclose the company’s annual revenue beyond saying it is in “double figures” of millions of dollars.
As Fortunereported in January, mobile security is a hot niche within the already hot overall field of cybersecurity. One analyst, who said early standouts include FireEye, Lookout, and Better Mobile, said pure mobile ventures (such as Wandera) could get acquired by larger firms seeking to provide a full suite of security services.