Despite stock-market turmoil and unease in the venture-capital community, cyber security companies are raising large rounds of financing from investors, whose tremendous appetite for high-tech defenses against cyber attacks is not expected to subside even in a market correction.

In the latest example, Bit9 + Carbon Black, a company that detects and protects servers from threats, is raising a fresh round of funding, investors told Reuters and the company confirmed. One investor estimates the company will raise approximately $50 million, on top of the roughly $120 million it has already raised.

The company declined to disclose the amount of funding.

"Financial markets are supporting companies like us really well," said Chief Executive Officer Patrick Morley.

And Zscaler, a cloud security company, also recently closed a new funding round, according to sources close to the company who declined to give the amount. This deal comes just more than a month after Zscaler raised $85 million.

The sector so far this year raised more than $2.3 billion globally, according to industry data, on a pace to top last year's total, and it is expected to remain a hot spot for big-dollar financing deals even during an economic downturn.

"One of the very few times a CEO is fired is when you are exposed to a security breach," said Venky Ganesan, managing director at Menlo Ventures. "This will be the last thing cut on the budget because nobody wants to lose their job."

Cloudflare Raises $110 Million

More funding was announced Tuesday, when CloudFlare, a company that offers both the ability to improve websites' performance and defend them from hackers, disclosed that it raised $110 million, bringing its total funding to $182 million in less than six years.

Even on the heels of the worst of the stock market turbulence in late August, cybersecurity software firm Tanium announced it raised $120 million from investors, and security companies Netskope and Okta announced $75 million financing rounds just days later.