NEW YORK — Security experts say passwords for more than 2 million Facebook, Google and other accounts have been compromised and circulated online, just the latest example of breaches involving leading Internet companies.

Some services including Twitter have responded by disabling the affected passwords. But there are several things you can do to minimize further threats – even if your account isn’t among the 2 million that were compromised.

Here are some tips to help you secure your online accounts:

ONE THING LEADS TO ANOTHER

When a malicious hacker gets a password to one account, it’s often a stepping stone to a more serious breach, especially because many people use the same passwords on multiple accounts. So if someone breaks into your Facebook account, that person might try the same password on your banking or Amazon account.

Suddenly, it’s not just about fake messages being posted to your social media accounts. It’s about your hard-earned money.

It’s particularly bad if the compromised password is for an email account. That’s because when you click on a link on a site saying you’ve forgotten your password, the service will typically send a reset message by email.

People who are able to break into your email account, therefore, can use it to create their own passwords for all sorts of accounts. You’ll be locked out as they shop and spend, courtesy of you.

If the compromised password is one you use for work, someone can use it to break into your employer’s network, where there are files with trade secrets or customers’ credit card numbers.

BETTER PASSWORDS

Many breaches occur because passwords are too easy to guess. There’s no evidence that guessing was how these 2 million accounts got compromised, but it’s still a good reminder to strengthen your passwords. Researchers at security company Trustwave analyzed the passwords compromised and found that only 5 percent were excellent and 17 percent were good. The rest were moderate or worse.

What makes a password strong?

• Make them long. The minimum should be eight characters, but even longer is better.

• Use combinations of letters and numbers, upper and lower case and symbols such as the exclamation mark. Try to vary it as much as you can. “My!PaSsWoRd-32” is far better than “mypassword32.”

• Avoid words that are in dictionaries, as there are programs that can crack passwords by going through databases of known words. These programs know about such tricks as adding numbers and symbols, so you’ll want to make sure the words you use aren’t in the databases. One trick is to think of a sentence and use just the first letter of each word — as in “tqbfjotld” for “the quick brown fox jumps over the lazy dog.”

• Avoid easy-to-guess words, even if they aren’t in the dictionary. Avoid your name, company name or hometown, for instance. Avoid pets and relatives’ names, too. Likewise, avoid things that can be looked up, such as your birthday or ZIP code.

One other thing to consider: Many sites let you reset your password by answering a security question, but these answers —such as your pet or mother’s maiden name— are possible to look up.

So try to make these answers complex just like passwords, by adding numbers and special characters and making up responses.