Capsule8 scored $15 million in Series B funding, joining a growing list of security firms that have attracted considerable financial attention. The latest funding round included ClearSky Security, Bessemer Venture Partners, and Rain Capital. The haul pushed the New York City-based company’s total funding to $23.5 million.

The company’s security platform is focused on securing Linux environments, including cloud, virtualized, and bare metal from zero-day attacks. Those are security vulnerabilities that are exploited by attackers immediately after they are found and before a patch can be deployed.

Capsule8’s Co-Founder and CEO John Viega said the platform is specifically designed to scale to large production environments and includes real-time detection, automated disruption, distributed telemetry, and third-party integration.

Viega said the firm plans to use the new funds to invest in its product line as well as sales and marketing. The company raised $6 million in its Series A round last September, which was led by Bessemer, and it launched the 1.0 version of its platform in April.

“Our first round was really about getting to 1.0 with our product,” Viega said. “But with the Series B we will invest more in the products but also in expanding our sales and marketing channels.”

Viega said the company was not specifically looking at a Series B round so soon after its Series A, but that reception to its platform expedited the process. One of those early partners was Lyft, which cited Capsule8’s ability to monitor its microservices-heavy environment.

“We weren’t out raising funds,” Viega said, noting that the company was planning to tap the funding market either later this year or next year. “But we had several firms that stayed close to us as we started launching our product, and they saw the response and wanted to try and jump the whole process.”

Viega said he has seen a lot of recent momentum around the container space, but also by organizations that are still making that transition to containers. “Some of them can still be on AWS [Amazon Web Services] but maybe not in containers yet,” he said, adding this is most often the case with larger, established organizations.

“Newer companies should be fully containerized, and media companies that are always building new apps are as well,” Viega said. “But larger enterprises are just now dipping their toe in the water of containers.”

Capsule8 was recently included as one of five container-focused security providers for Google’s Cloud Security Command Center. That platform provides a single pane of glass to view security alerts for clusters running in Google’s Kubernetes Engine (GKE).

Users tapping into the Google platform can view, organize, and index cluster assets across projects running in an organization. It also allows the linking of security findings to specific clusters, container images, and/or virtual machine (VM) instances.

“Ideally, organizations will be able to treat the public cloud as an app store for their infrastructure,” Viega said, noting those organizations would be able to quickly access the services they need from their cloud providers with just a single click.

Other security providers that are part of that program include Aqua Security, Stackrox, Sysdig Secure, and Twistlock.

As for competitors, Viega cited firms like Carbon Black instead of more container-focused vendors like Twistlock. In fact, he noted that Capsule8 has a number of mutual customers with Twistlock, which highlights the third-party integration aspect of its security platform.

As for Carbon Black, the firm in May raised $152 million in an initial public offering. It has since seen its stock price settle in at about a 20 percent premium to its IPO price.

Capsule8’s funding also comes on the heels of Cisco acquiring two-factor authentication startup Duo Security for $2.35 billion; Tennable raising $288 million through an IPO last month; and Zscaler scoring $192 million in its own IPO earlier this year.