Sept 19 (Reuters) - Cybersecurity firm KnowBe4 Inc said on Monday that Vista Equity Partners had offered to take it private for $4.22 billion in cash, the latest sign of private equity interest in a sector whose valuations have declined in this year's downturn.

The offer of $24 per share represents a premium of nearly 39% to KnowBe4's closing price on Sept. 16. Its shares have lost nearly a quarter of their value this year as of last close.

Private-equity firms have this year been taking advantage of the fall in valuations of technology companies due to worries over rising interest rates and an economic slowdown. The rise of hybrid work has also made cybersecurity firms attractive targets.

KnowBe4 provides security awareness training with simulated phishing attacks on its platform. The company's focus on a growing "must have" category from an enterprise perspective makes it attractive, according to Cowen analysts.

KnowBe4, whose shares surged 25% in the morning hours on Monday, said it had formed a special committee to review the offer.

The bid from Vista comes amid a string of large investments by the Austin, Texas-based fund this year. The firm has struck 21 deals so far including the $16.5-billion acquisition of cloud services firm Citrix Systems in January, according to investments tracker Tracxn. (Reporting by Yuvraj Malik in Bengaluru; Editing by Anil D'Silva and Shounak Dasgupta)