-- In July, September and November of 2005, alleged ID theft ring member Christopher Scott compromised two wireless access points operated by TJX at Marshalls department stories in Miami. Scott used his access to repeatedly transmit computer commands to TJX's servers storing credit card information in Framingham, Massachusetts. TJX, which also owns TJ Maxx, HomeGoods and other retail outlets, reported data breaches in January 2007.

Cybersecurity experts said companies worried about being victims can learn from the attacks. Companies storing personal information need to take a comprehensive approach to data security, including encryption of credit card databases, notifications of suspicious behavior inside their networks and limitations on who can access the data, security experts said.

Companies should also install software patches quickly and make sure they know were sensitive data is located on their networks, added Ted Julian, vice president of strategy and marketing for computer security vendor Application Security. Many companies do not know where all their sensitive data is stored, due to IT worker turnover and other factors, he said.

Companies also need to analyze their risks and take a targeted approach to fixing problems, said Sam Curry, vice president of product management at cybersecurity vendor RSA.

Attacks have changed in recent years, with more organized, targeted campaigns, Julian said. "The hackers are much more focused, and they'll try 38 doors, they'll try 100 doors," he said. "As soon as they find the one that's unlocked, they're on their way to the database. I don't know that a lot of [IT] people are getting $10 million in their budget to roll out a bunch of new security measures."

Companies should also examine whether the data they store is needed and how long they keep data, said Graham Cluley, senior technology consultant at Sophos, another cybersecurity vendor.

Companies have too long focused on perimeter defenses and not on protecting data inside their networks, Curry said. Retailers and other companies need to "wake up and take these threats seriously," Curry said. "Make the cost to the bad guys too high for them to do it."

The indictments announced Tuesday could raise awareness about cybersecurity, Curry added. And some high-profile convictions could serve as a deterrent to criminals.

But Curry and Cluley declined to point fingers at the retailers whose systems were compromised. While customers of the companies need to put pressure on them to improve security practices, the companies are victims, too, Cluley said.

"It'd be wrong to beat up the companies too much," Cluley said. "Competing companies shouldn't be feeling too smug, because how many of them can put their hands on their hearts and say, 'this could never happen inside our organization?'"