Accel pumps $50M into Tenable Network Security

Ten years into its existence and already profitable, Tenable Network Security has accepted its first outside investment — a $50 million infusion from venture capital firm Accel Partners. That’s a large investment any way you slice it, but Tenable is poised to capitalize on some very big opportunities.

Chief among them is the added focus companies are putting on preventing their networks from the types of attacks that have befallen seemingly everyone in the past year. On Tuesday, for example, news broke of an AntiSec hacker gaining millions of Apple UDID numbers by hacking an FBI agent’s laptop (although the FBI has denied that story). Tenable Founder and CEO Ron Gula says his company can help prevent this type of attack from happening.

The key to everything is Nessus, a product for scanning networks for vulnerabilities that could leave them open to attack. And while it performs traditional analysis such as malware detection and compliance audits (as well as less traditional ones such as scanning networks for sensitive content), Gula and his new investors are very excited about Nessus’s ability to give companies a real picture of what mobile devices are on their networks.

“People say BYOD,” Gula said, “but it’s really connect your own device to the network.” And, of course, networks have expanded in the world of mobile access and cloud services, so it’s not just a matter of knowing who’s on the LAN, but also who’s accessing your Exchange (s msft) server from a Starbucks halfway across the country.

Nessus lets users figure out how many mobile devices are accessing their network, as well as device information such as serial number, timestamp of the last connection, whether the phone has been jailbroken and what operating system versions they’re running. This type information can be particularly helpful, Gula said, because identifying, for example, a phone that hasn’t been updated in three years means identifying a possible avenue of attack via a vulnerability that has been patched in subsequent releases.

According to Accel partner Ping Li and vice president John Locke, their firm is also high on Tenable because of the volume of data the company generates. Tenable’s flagship customer is the entire U.S. Department of Defense, for which the company provides continuous monitoring of the agency’s network, but it also has more than a million other users ranging from Amazon (s amzn) to Dropbox to Walmart (s wmt). The obvious benefit of this large user base is that Tenable has a broad community from which to learn about potential threats in the wild, but Gula said the company is also working on research detailing how different industries compare when it comes to security practices.

As for why Tenable finally decided to take money from Accel (“We’ve been stalking these guys for a long time trying to convince them to let us invest,” Locke joked), it all comes down to growth. Already, the company has grown revenue by 550 percent over the past four years and has doubled its staff to nearly 200 employees in the past year. Gula said the money will help his company make sure its growing list of customers all get the attention and products they need, which means even more employees and a broader global presence.

The Tenable investment is also the latest in a series of investments Accel is making in established companies staring down potentially huge growth. In January, it led a $52.5 million round in veteran backup and software-recovery company Code42; in May, along with Sequoia Capital, Accel helped infuse decade-old marketing research company Qualtrics with $70 million.

Feature image courtesy of Shutterstock user kentoh.