Snyder joined Mozilla in 2006 from Microsoft, where she was a security strategist who worked on the company's security-driven Windows XP Service Pack 2 update and other products.

In an interview, Snyder talked about the state of browser security today and how companies must work together.

What is the biggest threat to users today?

My big concern is still the individuals out there trying to lure users into malicious sites, whether they're posing as a bank or a site they're familiar with. These things are painful. Users really feel it. The attacks come in through e-mail; they come in through websites. It's these broad-based attacks.

Do you see phishing attacks escalating this year?

They'll get worse as long as the methods they're using are successful. As a software development community, we can identify ways to mitigate these attacks ... so they'll eventually move to something else. We need software that is strong enough to mitigate threats that attackers haven't thought of yet. It's about building a multilevel security architecture so you're building in defence in depth. You're not building a defence against a security risk. You need multiple levels of security within an application because you don't know what's coming next. It's about building a secure application.

How far away are we from getting that kind of multilayered secure application?

We currently try to build Firefox that way, but there will always be things that no one has thought of yet. It's impossible to build a perfectly secure browser. That's not the goal. The goal is to build the safest browser we can. It's an ongoing process. It's not a goal where we'll say, "OK, we're done."

What's the biggest security problem with browsers today?

One of the things most difficult about browser security is that all browsers are designed to take content from an unknown site, and some of that content is going to be executable. Whether it's a Java applet or a Java script or ActiveX control, it's executing on a user's browser. You're enabling these robust applications on the Internet, this rich Web experience, while keeping the user and the machine safe. That's a pretty difficult thing for all of us to do. Software exists to support some function that enables a user or business. It's not for security to dictate to what the user should do. That's not how it should work.

IT keeps warning users to be cautious and not open attachments from unknown senders, for example. But users keep on doing it. Are users just dumb, as some experts say?

Users are not dumb. I get upset when I hear that. They're trying to accomplish a task. If the security interface gets in the way, or if the security interface isn't easy to understand, they're going to go around it, whether it's clicking through a certificate warning or trying to follow an email link that says your bank account is going to be frozen if you don't confirm your personal information details on this page. For all these things, the user is trying to accomplish a task. The attacker has created a sense of urgency. The easiest thing in front of them is to click on the link right in front of them.

What needs to be done about it?

We can build mechanisms into browsers and e-mail software that will mitigate users being hurt by these attacks. Firefox 3 has antiphishing and antimalware mechanisms that identify that a site has malware on it and blocks the user from visiting it.

Currently, it just throws up a UI [user interface] that is pretty hard to confuse that something serious has happened here. The UI will change until the product ships, but it will make it clear that this is a site that has malware on it, and it doesn't let you click through. It's not done until it ships, so it might look different in the final version. It depends on the feedback from the beta and from the community.

What change in Firefox 3 are you the most excited about?

I'm pretty excited about the malware-protection feature. And this is not a feature that users can feel. There's a lot of security work that goes in under the hood. Anytime you rewrite a piece of software with the security knowledge you have in 2007 compared to the knowledge you had in 2005 or 2006, it's going to be a stronger piece of software because you know more. Different threats have emerged, and [there are] different mechanisms for protecting them. A lot of memory management stuff has changed. That will be a pretty significant enhancement to overall security. A lot of security issues are memory management issues. Anything that mitigates those is a benefit to the entire application, as opposed to a single feature.

Last year, you had to deal with some bugs in the Firefox protocol handler. What did you learn from that whole experience?

One of the most interesting trends in application security is the interaction between multiple applications. We saw some of that this summer with the URI [Uniform Resource Identifier] issues. We saw that with Safari to Firefox, and IE to Firefox, and IE to Outlook and multiple applications. The URI stuff is just an example of a larger trend - interactions between multiple applications and vulnerabilities between them. It creates a situation where both vendors need to put protection in place to keep it from happening.

We got the fix out there, but that wasn't enough. We've got multiple applications so when you pass data from one application to the next, the application looks at the data like it's coming form the local operating system, but it came from the Internet. You can make it look like the content came from a relatively safe place. We got the fix out there but that wasn't enough ... because the other vendors need to create a fix for the other end of the problem. It's hard when multiple vendors are involved. Users might think Firefox shipped a fix and everything is fine, but ... they need Microsoft to ship a fix for Windows and IE.

How difficult is it for different companies to work together on problems like this?

It's difficult but in the end we all want the same thing, which is to protect our users. Once we understand the technical issues, it's just a matter of individuals doing the right thing for our users. I really do believe we all have that in mind.

Last summer, some people were accusing both sides - Mozilla and Microsoft - of finger-pointing instead of working together. Was that a problem?

I think what other people might interpret as finger-pointing is people trying to demonstrate that just because we fixed a part of it, it's not all fixed. A lot of what is really technical discussion of a problem is interpreted as finger-pointing. I did see a lot of technical information interpreted as finger-pointing. It's sensational and fun to read, but it's not really what's going on.

What's the most exciting technology on the horizon?

Oh, I'm excited about everything mobile. We're building a browser for mobile devices. In my personal life, I'm excited every time an application is out for my BlackBerry. I never would have thought I need to go into Twitter, but I do. It's a nice way to stay in touch with your friends. I love being in a new city and being able to look for a vegan restaurant and then find it on Google maps. That kind of stuff is incredible to me. I'm just so excited about the mobile space.

And finally, how did you get the name Window?

There's no story. I need to come up with a story. It's unfortunate because everyone wants to know ... and there's just nothing.