Yahoo Inc faced two significant data breaches, one in August 2013 and another in 2014, where unauthorized individuals accessed its systems and obtained personal information of many users. The compromised data included details such as contact information and security credentials. Yahoo acknowledged the 2014 breach in 2016, resulting in legal challenges, financial penalties, and criticism for their response time.

How many accounts were compromised?

The 2013 Yahoo data breach impacted all three billion user accounts, while the 2014 breach affected over 500 million user accounts.

What data was leaked?

The data leaked in the Yahoo breaches consisted of names, email addresses, phone numbers, birthdates, passwords, and security questions and answers, both encrypted and unencrypted.

How was Yahoo Inc hacked?

In the Yahoo data breaches, hackers employed various techniques to bypass security measures, such as manipulating web cookies to authenticate as other users without needing passwords. In the 2014 breach, the attacker copied a backup of Yahoo's User Account Database, containing over 500 million accounts, to a computer under their control. The exact methods used in the 2013 breach remain unclear.

Yahoo Inc's solution

In response to the hack, Yahoo Inc took several measures to enhance its security and prevent future incidents. This included hiring a dedicated chief information security officer, invalidating unencrypted security questions and answers, and asking potentially affected users to change their passwords. Yahoo also claimed that there was no evidence that the attackers were still in the system and that the attack was state-sponsored. Additionally, Yahoo implemented new security protocols and practices to better protect users' personal information stored in its databases.

How do I know if I was affected?

Yahoo Inc did reach out to affected users and asked them to change their passwords. If you were a Yahoo user and didn't receive a notification, you can visit Have I Been Pwned to check if your credentials were affected.

What should affected users do?

In general, affected users should:

• Change Your Password: Immediately update your password for the breached account. Make sure the new password is strong and unique, not previously used on any other platform.

• Reset Passwords for Other Accounts: If you've used the same or similar passwords for other online accounts, reset those as well. This is crucial as attackers often try using stolen passwords on multiple sites.

• Enable Two-Factor Authentication (2FA): Activate 2FA on the breached account and any other important online accounts. Consider enabling this additional security feature to significantly reduce the risk of unauthorized access.

• Monitor Your Accounts: Keep an eye on your accounts for any suspicious activity and report it immediately to the respective platform.

For more specific help and instructions related to Yahoo Inc's data breach, please contact Yahoo Support directly.

Where can I go to learn more?

If you want to find more information on the Yahoo Inc data breach, check out the following news articles:

• Yahoo Says 1 Billion User Accounts Were Hacked

• 500 Million Yahoo Users Affected by Data Breach – Password Change Recommended