500 Million Yahoo User Accounts Information Stolen, Largest Cybersecurity Breach Ever

500 Million Yahoo User Accounts Information Stolen, Largest Cybersecurity Breach Ever

Bob Lord, Yahoo's chief information security officer, has sent the notice of data breach email message below to Yahoo users, educating them about the data breach at Yahoo that occurred in late 2014, and telling them what they should do to help protect themselves. Yahoo has confirmed that approximately 500 million user accounts information have been stolen in the data breach, which is considered the largest cybersecurity breach ever.

The Yahoo Notice of Data Breach Email

From: Yahoo

Subject: Important Message Regarding Your Account Security

Date: Fri 9/23/16 3:56 PM



We are writing to inform you about a data security issue that may involve your Yahoo account information.

What Happened?

A recent investigation by Yahoo has confirmed that a copy of certain user account information was stolen I from our systems in late 2014 by what we believe is a state-sponsored actor. We are closely coordinating with law enforcement on this matter and working diligently to protect you.

What Information Was Involved?

The stolen user account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (the vast majority with bcrypt) and, in some cases, encrypted or unencrypted security questions and answers. Not all of these data elements may have been present for your account. The ongoing investigation suggests that stolen information did not include unprotected passwords, payment card data, or bank account information; payment card data and bank account information are not stored in the system that the investigation found to be affected.

What We Are Doing

We are taking action to protect our users:

We are asking potentially affected users to promptly change their passwords and adopt alternate means of account verification.

We invalidated unencrypted security questions and answers so they cannot be used to access an account.

We are recommending that all users who haven't changed their passwords since 2014 do so.

We continue to enhance our systems that detect and prevent unauthorized access to user accounts.

We are working closely with law enforcement on this matter.

Our investigation into this matter continues.

What You Can Do

We encourage you to follow these security recommendations:

Change your password and security questions for any other accounts on which you used the same or similar information used for your Yahoo account.

Review your accounts for suspicious activity.

Be cautious of any unsolicited communications that ask for your personal information or refer you to a web page asking for personal information.

Avoid clicking on links or downloading attachments from suspicious emails.

Additionally, please consider using Yahoo Account Key, a simple authentication tool that eliminates the need to use a password altogether.

For More Information

For more information about this issue and our security resources, please visit the Yahoo Security Issue FAQs page available at https://yahoo.com/security-update.

Protecting your information is important to us and we work continuously to strengthen our defenses against the threats targeting our industry.


Bob Lord

Chief Information Security Officer


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Comments, Questions, Answers, or Reviews

Comments (Total: 4)

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  • December 16, 2016 at 11:34 AM by an anonymous user from: Sutter Creek, California, United States

    I went through the steps provided to change my password and it won't let me. This is very upsetting. I need access to my account. There is no one to contact to get this solved and no number to call. It keeps sending me to the pages that I have already tried and it didn't work. I can receive my e-mails but can't get to me mail box or sign into my account. I need someone who can help me get to access my account. It tells me that Yahoo can't help me online. So someone needs to contact me asap.

  • December 15, 2016 at 5:29 PM by an anonymous user from: Scotts Valley, California, United States

    I'd like to change my password. But you won't say how. How?

    • December 15, 2016 at 5:49 PM by info

      <a href="https://ph.help.yahoo.com/kb/recover-reset-yahoo-password-sln27051.html" target="_blank">Click here</a> for instructions.

  • November 2, 2016 at 9:44 AM by an anonymous user from: Eugene, Oregon, United States

    How in the h**l can I prove I am not a robot? I have been trying to get into my yahoo account and can't get pass the password and when I ask for help I have to give my email address which gets me right back to "prove you are not a robot" and the continue button gets you nowhere because it does not respond! I am very tired of this game!

    btw-cannot access my email either!

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500 Million Yahoo User Accounts Information Stolen, Largest Cybersecurity Breach Ever