Imagine walking out of your house everyday and getting mugged.

A pickpocket swipes your wallet, which holds debit and credit cards, health insurance information and the PIN number to an online stock-trading account. Even if your accounts are restored by the end of the day, the next morning a different pickpocket will go after your information all over again.

This is a wild tale, of course, unless it refers to a computer network without any form of Internet security, and the mugger is a worm or a virus infecting the system.

Chris Rouland, chief technology officer at IBM's Internet Security Systems, doesn't care who's getting into the computer network. His only concern is how the viruses got there in the first place.

Rouland, who joined ISS in 1998, helped develop the company's X-Force team, the research-and-development group that tries to fight off computer worms before they ever reach a company's network. ISS is a homegrown company that outlived the dot-com boom. IBM bought it in 2006 for $1.3 billion.

Rouland talked about how cybercrime has transformed from bored teenagers hacking into computers just because they can to huge underground rings of sophisticated thieves who lift credit card information or crash from an online casino's Web site and then call the owner to say, "If you want your business back, wire me $100,000."

Q: Do other people think it's cool that you work with a group that goes by the name X-Force?

A: That's how I got the job here. I sent my friend an e-mail and said, "What's this X-Force thing?" It's really exciting. X-Force has matured enough in the industry that people say "I had to come work here" and get it on their resume.

Q: How has the explosion of the information age made your job harder?

A: When I started off at ISS, we had a busy month 10 years ago if we were tracking 20 new vulnerabilities. Now, there's one every hour, a new way someone can break into your [fire]wall. There are so many flaws out there.

The threat has changed so much. Clients used to be worried about their Web site being defaced. Today they are worried about going out of business. I would characterize chasing a patch as a fool's chase.

Q: A patch?

A: Here's an example. Microsoft announces vulnerabilities in their system every second Tuesday of the month. Once they announce that, the bad guys can get to those and use them if we don't take them and apply a patch.

Q: You and your co-workers mention "getting ahead of the threat" a lot. What does that mean?

A: It's pre-emptive protection. We're inoculating our own personal computers —- literally give them a sample of a virus. But you can't inoculate for 100 million viruses a year because you'd constantly be inoculating yourself. So you have to knock out the way they affect your computer and know the way they propagate.

Q: Tell me something scary.

A: Between one in five and two in five computers are currently compromised: A bad guy has taken over it. They are opportunistic and have the ability to take hundreds of thousands of computers. They can shut down an entire country. They can take the country off the Internet for several days.

Q: What keeps you up at night?

A: I sleep pretty well! (laughs) The bad guys are on the inside —- so while we've built a good wall, there's one vulnerability every hour, hundreds of viruses a year. We bundle it all into one term called "malicious code." Look at the security space [industry], it brings in between $40 billion and $50 billion a year in revenue, but the Department of Justice estimates that online fraud is $100 billion. So, there's $100 billion that the bad guys have, and that's four times the amount companies typically spend on fighting viruses. Do we need help in this area? Probably.

Q: I understand there's a strong connection between ISS and Georgia Tech.

A: (Referring to ISS co-founders Tom Noonan and Chris Klaus) Tom was a Tech grad. Chris dropped out of Tech. The computer science building is named after Chris. Georgia Tech is a real anchor for the Atlanta tech community. We try and keep that local. We want to invest there because we want to recruit their students.

Q: Why do you have a movie poster of "Reservoir Dogs" in your office?

A: My wife brought that in. She wrote all of our names and who she thought we were. I took off the names. (laughs) I was [Harvey] Keitel.

THE CHRIS ROULAND FILE

> Age: 36

> Hometown: Reston, Va. Has lived in Atlanta for 10 years.

> Family: Wife, Gigi; one daughter, Eva, 3; and another daughter due soon whom the couple plans to call Scarlett.

> Pets: A Saint Bernard named Maggie and a boxer named Victor.

> Station playing on car radio: Fox News.

> Last book read: "Ghost Wars" by Steve Coll.

> Last restaurant: Imperial Fez.