What you need to know about the Heartbleed bug

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NEW YORK — Millions of passwords, credit card numbers and other personal information could be at risk as a result of a major breakdown in Internet security revealed earlier this week.

NEW YORK — Millions of passwords, credit card numbers and other personal information could be at risk as a result of a major breakdown in Internet security revealed earlier this week.

A confounding computer bug called “Heartbleed” is causing major security headaches across the Internet as websites scramble to fix the problem and Web surfers wonder whether they should change their passwords to prevent theft of their email accounts, credit card numbers and other sensitive information. The breakdown revealed earlier this week affects a widely used encryption technology that is supposed to protect online accounts for a variety of online communications and electronic commerce.

Security researchers who uncovered the threat are particularly worried about the lapse because it went undetected for more than two years. They fear the possibility computer hackers might have been secretly exploiting the problem before its discovery. It’s also possible no one took advantage of the flaw before its existence was announced late Monday.

Although there is now a way to close the security hole, there are still plenty of reasons to be concerned, said David Chartier, CEO of Codenomicon. A small team from the Finnish security firm diagnosed Heartbleed while working independently from another Google Inc. researcher who also discovered the threat.

“I don’t think anyone that had been using this technology is in a position to definitively say they weren’t compromised,” Chartier said.

The damage caused by the “Heartbleed” bug is currently unknown. The security hole exists on a vast number of the Internet’s Web servers. While it’s conceivable the flaw was never discovered by hackers, it’s nearly impossible to tell.

There isn’t much people can do to protect themselves until the affected websites implement a fix. Here are answers to some common questions about Heartbleed and how you can protect yourself:

Q: What is Heartbleed and why is it a big deal?

A: Heartbleed affects the encryption technology designed to protect online accounts for email, instant messaging and e-commerce. It was discovered by a team of researchers from the Finnish security firm Codenomicon, along with a Google Inc. researcher who was working separately.

It’s unclear whether any information has been stolen as a result of Heartbleed, but security experts are particularly worried about the bug because it went undetected for more than two years.

Q: How does it work?

A: Heartbleed creates an opening in SSL/TLS, an encryption technology marked by the small, closed padlock and “https:” on Web browsers to show that traffic is secure. The flaw makes it possible to snoop on Internet traffic even if the padlock is closed. Interlopers can also grab the keys for deciphering encrypted data without the website owners knowing the theft occurred.

The problem affects only the variant of SSL/TLS known as OpenSSL, but that happens to be one of the most common on the Internet.

Q: So if the problem has been identified, it’s been fixed and I have nothing to worry about. Right?

A: It depends on the website. A fixed version of OpenSSL has been released, but it’s up to the individual website administrators to put it into place.

Yahoo Inc., which has more than 800 million users around the world, said Tuesday that most of its popular services — including sports, finance and Tumblr — had been fixed, but work was still being done on other products that it didn’t identify.

Q: So what can I do to protect myself?

A: Ultimately, you’ll need to change your passwords, but that won’t do any good until the sites you use adopt the fix. It’s also up to the Internet services affected by the bug to let users know of the potential risks and encourage them to change their passwords.

Q: I plan to file my income taxes online. Is that safe considering how much personal information is involved?

A: The IRS released a statement on Wednesday saying that it’s not effected by the bug or aware of any related security flaws. It advised taxpayers to continue filing their returns as they normally would in advance of the April 15 deadline.

But Canada’s tax agency on Wednesday temporarily cut off public access to its electronic filling services just three weeks before its tax deadline citing Heartbleed-related security concerns.

The Canada Revenue Agency said it’s working to restore secure access as soon as possible. The agency said consideration will be given to taxpayers who are unable to comply with their filing requirements because of the interruption.

AP writers Anick Jesdanun and Michael Liedtke contributed to this story.