(Reuters) - Private equity firm TPG said on Tuesday it would lead a $15 million funding round for Tel Aviv-based cyber security firm GuardiCore through its growth investment arm.

The early-stage investment in GuardiCore is the latest addition to TPG’s portfolio of cyber security investments that includes Intel’s Corp’s former security division McAfee.

GuardiCore, which has raised $48 million in funding to date, is focused on protecting data centers from cyber security threats. Through its software, it puts up virtual walls between servers so that viruses are contained before they spread and infect more of the data of a company.

Hundreds of security startups have sprouted in recent years, promising “next-generation” technologies to fight cyber criminals, government spies and hacker activists, who have plagued some of the world’s biggest corporations.

Venture capital investors have been trying to spot winners in a crowd of younger companies. They can make for risky investments, because sophisticated cyber attacks can make such software obsolete very quickly.

GuardiCore Chief Executive Pavel Gurvich said his company’s products are being used in some of the world’s largest corporations such as Santander Brasil, a unit of Madrid-based Banco Santander SA.

Greenfield Partners, a joint venture between TPG and Israeli investor Yuda Doron that invests in early-stage technology companies, is co-leading the funding round. The valuation of Guardicore was not disclosed.

TPG’s other cyber security investments include Tanium and Zscaler. Zscaler is expected to go public later this year, Reuters has reported.

This is the second investment for TPG-backed Greenfield, which invested in Avanan, a New York- and Israel-based cloud security company last year.