Cyberintruders used the Internet to crack into at least 18 computer servers at the World Bank Group last July. The intrusion, revealed Friday in a FoxNews.com story by veteran investigative reporter Richard Behar, underscores how relentlessly criminals probe corporate IT systems, especially banks, say tech-security experts. "The sophistication, resolve and organization of cybercriminals are growing exponentially," says Tom Kellerman, vice president of security awareness at Core Security Technologies. Kellerman served as a senior risk-management specialist at the World Bank from 2000 to 2006; he helped set up the bank's cyberdefenses. "Every financial organization is under siege," he says. World Bank spokesman Carl Hanlon confirmed the authenticity of bank memos obtained by Behar describing how bank officials discovered — and reacted to — the cyberbreak-in. "The bottom line is that at no point was any sensitive information accessed," Hanlon said in a phone interview. That assertion drew skepticism in tech-security circles. Several security experts noted that cyberthieves are experts at stealing data without leaving a trace. "It's not like when you steal the Mona Lisa and there's a blank space left on the wall," says Sophos researcher Graham Cluley. One bank memo lists the breached servers and makes this assessment: "As of 9/9/08 we have determined that 5 of the compromised servers contain sensitive data, and care must be taken to determine the amount of information that may have been transmitted outside of the World Bank Group." Michael Maloof, CTO of TriGeo Network Security, notes that cyberintruders routinely install programs to systematically harvest data, while also continually "sniffing" for access to other computers in the network, including those of partners and customers. Hanlon acknowledged that "like other public and private institutions, the World Bank has repeatedly experienced hacking attacks on its computer systems and is constantly updating its security to defeat these." Banks, indeed, are not the only targets. Corporate intrusions in general are on the rise, says Phil Neray, vice president at database security firm Guardium. Cybercrooks seek out PCs used by privileged insiders so they can access sensitive databases and other PCs. "Many organizations don't have any real-time monitoring or alerting mechanisms in place to identify unauthorized activities," Neray says. Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more