Security companies seem to be very 'hot' for investors at the moment. Avast Software has just announced that it has received a significant investment, in the amount of $100 million, from venture capital firm Summit Partners.

The investor will receive a minority stake in the Czech security software company. Scott Collins, a Managing Director of Summit Partners will also join Avast's board of directors.

"Summit Partners' investment is a vote of confidence in our disruptive 'freemium' business model, which combines a full-fledged free product with a premium one," Vince Steckler, CEO of AVAST Software, said in a statement. "This approach is already upsetting the traditional antivirus market."

According to the company, the move to offer a free version of its antivirus software proved very successful and it helped it become one of the largest security companies around, at least in terms of users.

Avast says that its software protects one in five computers in the world, though that may be a bit misleading. Still, it has over 100 million registered users, a significant boost from when the company first started offering a free version of its software.

While free antivirus software is not exactly uncommon, Avast stands out since it offers real-time protection out-of-the-box. The strategy has paid off, according to the company.

"'Freemium' is the wave of the future," Steckler added. "Together with Summit Partners, we will continue our strategy of providing a quality, free antivirus solution to the widest possible audience. We have no plans to change our approach and conform to the classic retail positioning model."

Just last week, hardware giant Intel bought McAfee, one of the largest security software companies in the world, in an all-cash deal valued at $7.68 billion. It was a rather surprising move from the chip-maker, but, with the Avast investment, it seems that the market is very favorable for security companies.