Opt out of marketing data bases! Do it now! And don't give out any personal information in response to an email, even if it appears to come from your bank or favorite store.

Another major hacker attack last week exposed the names and emails of millions of consumers to cyber criminals — and you might be on the list. As a practical matter, you can't get out of all of the massive data banks that hold your personal data. Even the names of people who opted out might be retained. But you can do your best to minimize your risk.

The latest breach occurred at a company called Epsilon, a division of Alliance Data Systems Corp. Epsilon holds the names, email addresses, marital status, credit data, and other personal information of 235 million people. It mines the names for personal shopping habits, interests, life changes such as marriage or moving, and credit capacity, and sends out targeted marketing pitches. If you get a 30 percent discount offer from Target, to take just one example, it probably came from Epsilon. The company broadcasts 40 billion email messages annually, to consumers it considers most likely to buy.

The hackers who broke into Epsilon's computer systems got names and emails tied to the banks and stores they patronize. That's especially dangerous. Using that information, they can send you notices that evade your spam filter and that you're likely to open. Say, for example, that you get an email apparently from Citibank, warning that your account has been breached and asking you to verify your personal information. If you log on with your password and bank ID, you've opened the door to a crook who can clean you out. The industry calls it "spear-phishing."

Once thieves have your password, they can worm their way into many of your accounts. That's because most of us stick with a limited number of passwords, because remembering different ones is such a pain.

The Epsilon break-in exposed the the customers of at least 43 banks and businesses (and probably more), including the financial institutions Ameriprise, American Express, Barclays Bank, Capital One Financial Corp, Citigroup, JPMorgan Chase, and U.S. Bancorp, as well as BestBuy, Ethan Allen furniture, Kroger grocery chain, the Home Shopping Network, LL Bean, Target, Visa, Walgreens, and the Hilton and Marriot hotel chains. The College Board said that students have also been exposed. You'll find the full list at DataBreaches.net.

Major data breaches occur all the time, they just don't get as much publicity as Epsilon did. You can read about them on websites such as KrebsOnSecurity and SecurityWeek. You're also being phished by phone (vishing), or with lures sent by text message (smishing).

So much of your personal data is swirling around the world that you cannot fully protect yourself. But here are some steps you can take to lower your risk:

After taking all these actions, are you safe from international financial thieves? Unfortunately, no. Anyone with banking, retail, email, college, or credit relationships will have their data stored somewhere, and the institution might not have spent enough money to keep it safe. Someday the database industry will be slapped with a massive lawsuit, and then maybe they'll start taking encryption and other advanced security measures more seriously.