Persistence pays. Once, when Winkler was posing as a person from corporate who needed a tour of a facility, he was interrupted by a manager who asked why he was being shown around. Winkler gave him a West Coast phone number. "It was 8 a.m. on the East Coast, so by the time he could reach anyone, I was out of the state," he says.
Of course, not all spies take the low-tech approach; an increasing number are taking advantage of known insecurities in Web applications, according to a SANS Institute report on the Top 20 Internet security risks of 2007. The report names vulnerable Web applications as the top new risk, enabling Web sites to be poisoned, data stolen, and computers connected to the Web site compromised. In 2008, the report says, Web application attacks will grow substantially.
How to stop them: Web scanning tools can help find application vulnerabilities, especially when combined with source code review tools and application penetration tests. The SANS Institute also recommends inspecting the Web application framework's configuration and hardening it appropriately. "No one should be engaged to write Web applications unless they can pass the GSSP Secure Software Programming exam that covers the essential security skills and knowledge that developers need to produce more secure applications," the report concludes.
An efficient way for spies to work is to pay inside employees to steal information. Often, there's nothing high-tech about the maneuver, Winkler says; employees simply use their existing access rights to download greater volumes of data than they ordinarily should.
How to stop them: Use a combination of access control and proactive auditing, Winkler says. For instance, if customer service representatives generally access 30 records a day, he says, and suddenly a couple of people are accessing 100 a day, that's a red flag. So is an employee who suddenly begins accessing data from home, adds Ken van Wyck, a principal consultant at KRvW Associates, a security consultancy in Alexandria, Va. "You're looking for drastic changes in behavior," he says, which can be detected through statistical anomaly detection programs.
It's also important to use the access control capabilities of the operating system, van Wyck adds. "People don't take the time to configure these very well," he says. "Many employees can access more than they need to do their job."
Another countermeasure is to disable the USB ports through the system's password-protected BIOS or use centralized tools that restrict the use of ports and external devices, according to the SANS Institute report, making it more difficult for wannabe spies to easily export the data.
Spies that get inside buildings can do other damage, such as implementing keystroke loggers. Some of these devices e-mail the keystrokes of anyone using the computer to a predefined e-mail address, while others store keystrokes in flash memory. Many are nearly impossible to detect, such as those that attach directly to the keyboard connector. Wood knows one case where spies pretending to be office cleaners nearly stole $300 million pounds from a U.K. bank using this technique.
How to stop them: Physical inspection of the computer is the only way to detect a keystroke logger, Wood says. Because of the impracticality of doing that, one company that Wood knows of now glues all its keyboards into the system unit.