Computer hackers have taken to stealing data the easy way -- by eavesdropping on phone and e-mail conversations to find the keys to seemingly impregnable networks, security experts say.

The danger of attacks with insider information was illustrated earlier this month with the arrest of a California man accused of breaking into mobile phone network T-Mobile USA Inc.'s database and reading e-mails and files of the U.S. Secret Service, and by the exploits of a hacker who breached a hospital's database and changed mammogram results.

The nature of threats to network security has changed as sophisticated hackers learned to tap into sensitive information flowing through telecommunications' servers, especially those that provide wireless and Internet access.

"Telecom providers are probably one of the main targets for malicious attackers because they control communications for everybody," said Ralph Echemendia, head of Intense School, which trains executives in network security risks.

CANDY FROM A BABY
Hackers may con their way into a phone network by posing as phone company tech employees to get passwords into the network. Then they could essentially tap phones or search for personal data like text files or even camera phone photos.

"(Hackers) will sit there and listen in, waiting to get valuable information," Echemendia said. "Once they have a foothold on one system they go through the same process to find other hosts."

Security experts at Intrusic Inc. captured 4,466 passwords and 103 master passwords allowing global access to corporate databases while monitoring one Internet service provider for a 24-hour period, Intrusic President Jonathan Bingham said.

"It's like stealing candy from a baby," Bingham said. "The malicious attacker will assume the identity of a person whose password they have stolen through this passive sniffing and they end up entering this organization as a legitimate user."

Once inside, it takes the hacker seconds to set up back doors that allow access to the database at any time to do more spying, data theft or worse.

BEST PRACTICES
Most hackers, however, are after information -- passwords, social security numbers and birth dates -- that they can sell or use to penetrate bank and credit card accounts, Forrester Research Inc analyst Laura Koetzle said. "Telecoms and cable companies are pretty high on the list simply because of their huge customer bases," Koetzle said. "If they can crack T-Mobile's database they can get user names and passwords for (millions of) subscribers at all once."

In a statement, T-Mobile, a Deutsche Telekom AG unit, said it "quickly put in safeguards to prevent further access and began an investigation" after a hacker broke into its internal computer systems in 2003 and accessed data on 400 customers.

As more companies shift business functions to the Internet and allow workers to access secure systems from off-site, it becomes tougher to guard against insider attacks and easier for hackers to breach the system, said Stan Quintana, director of managed security services at AT&T Corp .

"All these types of environments are requiring a higher level of security ... of data in transit," he said.

The key to cutting down on damage from inevitable insider attacks is to constantly monitor data flow and train employees to guard passwords and access to computers, he said.

He added that among the "best practices" AT&T advocates is that its customers periodically hack into their own networks.

From Reuters