We are writing to update you about a data security issue previously announced by Yahoo in December 2016. Yahoo had already taken certain actions in 2016, described below, to help secure your account in connection with this issue.
On 14 December 2016, Yahoo announced that, based on its analysis of data files provided by law enforcement agencies, the company believed that an unauthorised party had stolen data associated with certain user accounts in August 2013. Yahoo notified the users that it had identified at that time as potentially affected. We have recently obtained additional information and, after analysing it with the assistance of outside forensic experts, we have determined that your user account information was also likely to have been affected.
What Information Was Involved?
The stolen user account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords (using MD5) 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 investigation indicates that the stolen information did not include passwords in clear text form, payment card data or bank account information. Payment card data and bank account information are not stored on the system that we believe was affected.
What We Are Doing
In connection with the December 2016 announcement, Yahoo took action to protect users (including you) beyond those identified at that time as potentially affected. Specifically:
- Yahoo required potentially affected users to change their passwords.
- Yahoo also required all other users who had not changed their passwords since the time of the theft to do so.
- Yahoo invalidated unencrypted security questions and answers so that they cannot be used to access an account.
What You Can Do
Whilst Yahoo has already taken action to help secure your account, we encourage you to consider the following account security recommendations:
- Change your passwords, as well as your security questions and answers, for any other accounts on which you used the same or similar information as for your Yahoo account.
- Review your accounts for suspicious activity.
- Be cautious if you receive any unsolicited communications that ask for your personal information or refer you to a web page asking for personal information.
- Avoid clicking links or downloading attachments from suspicious emails.
For More Information
For more information about this issue and our security resources, please visit the Yahoo 2013 account security update FAQs page, available at https://help.yahoo.com/kb/index?locale=en_GB&page=content&y=PROD_ACCT&id=SLN28451&actp=productlink.
We value the trust that our users place in us, and the security of our users remains a top priority.
Chief Information Security Officer