Winkler, author of "Corporate Espionage" and the forthcoming book "Security for System and Network Administrators" due out in March, recently revised his estimate of the number of hackers, saying there now are 50,000 to 100,000 worldwide -- up from an estimated 35,000 to 50,000 two years ago. They are mostly teenagers who know how to exploit known vulnerabilities, according to Winkler.
Beyond that, the number of hackers who are good enough to write their own tools has grown from 1000 to somewhere between 5000 and 10,000, and the number of most highly skilled hackers now stands at about 1000.
"I used to say there were only . . . a few hundred (in the latter category)," Winkler said yesterday in an interview at a conference on surveillance here. "These are people who like to play with software and figure out how to find exploits into the software. That requires lots of good technical talent and knowing how to do software testing."
Systems administrators should follow a few basic steps to protect their systems from hackers, such as obtaining service packs that supply fixes to known vulnerabilities, which are what the majority of hackers usually try to exploit, said Winkler, a former analyst and computer expert at National Security Agency. As many as 95 percent of systems administrators don't do this, he added.
"You can get rid of all the ankle biters by using basic things, and people don't realise that," Winkler said.
Unless the fixes are in place, a hacker can download a scanning tool from a hacker Web site and run it against a TCP/IP address, and it will let the hacker know that the company is using an old version of Windows 95, for example. The next step is to attack the code using tools also available on the Internet that exploit the known vulnerabilities in that particular software.
Another basic precaution against the small-fry hacker is to turn on security features built into the operating system, Winkler said.
To guard against more sophisticated hackers, administrators should make sure systems are configured to maximize security. Many systems are configured in such a way that they allow users to share too much data, for example, which is an indication that poor administrator training is an underlying problem, Winkler said.
One of the problems for new administrators is they are rarely told that in addition to keeping the system running, they must also make sure it's secure. If they are given that command, it usually comes in the form of a superficial requirement to prevent passwords from being breached and old accounts from being reactivated, Winkler said.
Microsoft often takes the rap for security vulnerabilities from critics who say the company fails to properly test its software. Winkler said that situation has improved at Microsoft, even as the company faces a more testing challenge because of the added functionality that's being built in to Windows.
"The more functionality you have, the more likelihood there is for a security vulnerability, and Windows NT just keeps building more and more functionality in there," Winkler said.
In addition to the technical weaknesses, Winkler said that procedural weaknesses often leave companies vulnerable to system intrusions. For example, he successfully compromised the security of a bank using a combination of information he found on the Internet and information he obtained by calling employees and convincing them he had legitimate reasons for needing things like passwords and employee ID numbers.
He would not have succeeded if the bank had required its employees to ask for identification when they were asked their passwords, or if they had required their employees to hang up and phone back.