Getting your Trinity Audio player ready...

Threat vulnerability assessment platform Risk I/O raised $4 million and named a new CEO, the company announced Tuesday.

The additional funding was driven by existing investor Palo Alto-based Costanoa Venture Capital, which led the round and gained a board seat. It is an extension of a Series A round raised in November 2012 and brings Risk I/O’s total funding to $10.5 million.

“They were looking to, based on all our recent success, up their equity stake in the company and probably even more importantly get a board seat,” said co-founder and former CEO Ed Bellis, who now heads up product and strategy at Risk I/O.

Palo Alto-based Tugboat Ventures, Menlo Park-based US Venture Partners and Chicago-based Hyde Park Angels — all existing investors — also participated in the round.

Karim Toubba, previously vice president of worldwide security channels at Sunnyvale-based Juniper Networks, took over as CEO two weeks ago. Bellis said it was always part of the plan to find a new CEO who could focus on sales and marketing for the four-year-old company. He called himself a “product and technology guy” and said Toubba would bolster the company’s growth efforts.

“We’re at the stage of the company where we’re beyond product-market fit,” Bellis said. “It’s all about scaling and ramping up customers and revenue as fast as possible right now.”

The Chicago-based company has 20 full-time employees plus some contractors that work in its offices here, in San Francisco and remotely. In April, Risk I/O announced a partnership with Dell Secureworks, which Bellis said is a major drive of recent growth. In August, Risk I/O inked a product partnership deal with Verisign through which it licenses Verisign’s iDefense vulnerability reports.