Proofpoint Wants To Knock Out Hot Security Startup FireEye

But Proofpoint has no intention of letting FireEye upend the $11 billion email security products market. Proofpoint, a company best known for its anti-spam products, acquired Armorize Technologies on Friday for $25 million to go head-to-head with FireEye.

FireEye makes a product that solves a really hard problem. It protects against something called "advanced persistent threats" when hackers use all means possible to break into a particular network. It offers an appliance, a device that combines hardware and software, to run suspicious code or open emails in a protected area to see what they do. The process takes a fraction of a second.

FireEye landed in the spotlight when it managed to hire former McAfee CEO Dave DeWalt. In January, it nabbed a $50 million investment ($85.5 million to date) and a $1.25 valuation. It hopes to raise $175 million in its IPO.

Proofpoint was one of the hot IPOs of 2012 and it wants to take on FireEye's turf. Instead offering an appliance, the Armorize tech works in the cloud, Proofpoint CEO Gary Steele told us. That's going to make its tech powerful and affordable, he said.

As for how well the Armorize investors did, the company never announced how much it raised. But one seed investor was Ambient Sound Investments, the VC firm created by the founders of Skype.