Open Source entrepreneur

There is a belief that open source software is more secure.
A lot of people are using firefox because they thinks it's more secure than Internet Explorer.
According to Symantec that's not the case. In the past 6 months they have recorded twice as many vulnerabilities in Mozilla/Firefox than in Internet Explorer.
I've seen similar reports on some Linux distributions like Fedora versus Microsoft servers.

So is open source really more secure?

Yes it is.
Because the development and support process is much more adapted to security threats.
Flaws in open source applications are generaly fixed and deployed much more quickly.
The risk and danger of those flaws is much more limited, by design. You can't get Administrator access from an open source web browser.

What may explain why you have more identified vulnerabilities on open source software is that its source code is read by thousands of people.
So you can expect a mature open source application to reach a point where it will have no security flaws, or a very small number.
This didn't happen for Internet Explorer, which hasn't evolved much in the past 5 years and is still full of security flaws.